Protein Biosynthesis: The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.Peptide Elongation Factor Tu: A protein found in bacteria and eukaryotic mitochondria which delivers aminoacyl-tRNA's to the A site of the ribosome. The aminoacyl-tRNA is first bound to a complex of elongation factor Tu containing a molecule of bound GTP. The resulting complex is then bound to the 70S initiation complex. Simultaneously the GTP is hydrolyzed and a Tu-GDP complex is released from the 70S ribosome. The Tu-GTP complex is regenerated from the Tu-GDP complex by the Ts elongation factor and GTP.Ribosomes: Multicomponent ribonucleoprotein structures found in the CYTOPLASM of all cells, and in MITOCHONDRIA, and PLASTIDS. They function in PROTEIN BIOSYNTHESIS via GENETIC TRANSLATION.RNA, Transfer, Amino Acyl: Intermediates in protein biosynthesis. The compounds are formed from amino acids, ATP and transfer RNA, a reaction catalyzed by aminoacyl tRNA synthetase. They are key compounds in the genetic translation process.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Peptide Chain Elongation, Translational: A process of GENETIC TRANSLATION, when an amino acid is transferred from its cognate TRANSFER RNA to the lengthening chain of PEPTIDES.Abrin: A toxic lectin from the seeds of jequirity, Abrus precatorius L. Very active poison. Five different proteins have so far been isolated: Abrus agglutinin, the component responsible for: hemagglutinating activity, & abrins a-d, the toxic principals each consisting of two peptide chains are held together by disulfide bonds.Peptide Elongation Factors: Protein factors uniquely required during the elongation phase of protein synthesis.RNA, Transfer: The small RNA molecules, 73-80 nucleotides long, that function during translation (TRANSLATION, GENETIC) to align AMINO ACIDS at the RIBOSOMES in a sequence determined by the mRNA (RNA, MESSENGER). There are about 30 different transfer RNAs. Each recognizes a specific CODON set on the mRNA through its own ANTICODON and as aminoacyl tRNAs (RNA, TRANSFER, AMINO ACYL), each carries a specific amino acid to the ribosome to add to the elongating peptide chains.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Geobacillus: A genus of gram-positive, endospore-forming, thermophilic bacteria in the family BACILLACEAE.Amino Acyl-tRNA Synthetases: A subclass of enzymes that aminoacylate AMINO ACID-SPECIFIC TRANSFER RNA with their corresponding AMINO ACIDS.Bacterial Proteins: Proteins found in any species of bacterium.Ribosomal Proteins: Proteins found in ribosomes. They are believed to have a catalytic function in reconstituting biologically active ribosomal subunits.Peptide Chain Initiation, Translational: A process of GENETIC TRANSLATION whereby the formation of a peptide chain is started. It includes assembly of the RIBOSOME components, the MESSENGER RNA coding for the polypeptide to be made, INITIATOR TRNA, and PEPTIDE INITIATION FACTORS; and placement of the first amino acid in the peptide chain. The details and components of this process are unique for prokaryotic protein biosynthesis and eukaryotic protein biosynthesis.Poly U: A group of uridine ribonucleotides in which the phosphate residues of each uridine ribonucleotide act as bridges in forming diester linkages between the ribose moieties.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Kinetics: The rate dynamics in chemical or physical systems.Transfer RNA Aminoacylation: The conversion of uncharged TRANSFER RNA to AMINO ACYL TRNA.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Keratins, Type II: A keratin subtype that includes keratins that are generally larger and less acidic that TYPE I KERATINS. Type II keratins combine with type I keratins to form keratin filaments.Cycloheximide: Antibiotic substance isolated from streptomycin-producing strains of Streptomyces griseus. It acts by inhibiting elongation during protein synthesis.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Glutamate-tRNA Ligase: An enzyme that activates glutamic acid with its specific transfer RNA. EC Elongation Factor G: Peptide Elongation Factor G catalyzes the translocation of peptidyl-tRNA from the A to the P site of bacterial ribosomes by a process linked to hydrolysis of GTP to GDP.Biosynthetic Pathways: Sets of enzymatic reactions occurring in organisms and that form biochemicals by making new covalent bonds.GTP Phosphohydrolase-Linked Elongation Factors: Factors that utilize energy from the hydrolysis of GTP to GDP for peptide chain elongation. EC 3.6.1.-.Protein Synthesis Inhibitors: Compounds which inhibit the synthesis of proteins. They are usually ANTI-BACTERIAL AGENTS or toxins. Mechanism of the action of inhibition includes the interruption of peptide-chain elongation, the blocking the A site of ribosomes, the misreading of the genetic code or the prevention of the attachment of oligosaccharide side chains to glycoproteins.RNA, Transfer, Arg: A transfer RNA which is specific for carrying arginine to sites on the ribosomes in preparation for protein synthesis.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Genetic Code: The meaning ascribed to the BASE SEQUENCE with respect to how it is translated into AMINO ACID SEQUENCE. The start, stop, and order of amino acids of a protein is specified by consecutive triplets of nucleotides called codons (CODON).Methionine-tRNA Ligase: An enzyme that activates methionine with its specific transfer RNA. EC An essential aromatic amino acid that is a precursor of MELANIN; DOPAMINE; noradrenalin (NOREPINEPHRINE), and THYROXINE.RNA, Transfer, Phe: A transfer RNA which is specific for carrying phenylalanine to sites on the ribosomes in preparation for protein synthesis.Peptide Biosynthesis: The production of PEPTIDES or PROTEINS by the constituents of a living organism. The biosynthesis of proteins on RIBOSOMES following an RNA template is termed translation (TRANSLATION, GENETIC). There are other, non-ribosomal peptide biosynthesis (PEPTIDE BIOSYNTHESIS, NUCLEIC ACID-INDEPENDENT) mechanisms carried out by PEPTIDE SYNTHASES and PEPTIDYLTRANSFERASES. Further modifications of peptide chains yield functional peptide and protein molecules.Peptide Chain Termination, Translational: A process of GENETIC TRANSLATION whereby the terminal amino acid is added to a lengthening polypeptide. This termination process is signaled from the MESSENGER RNA, by one of three termination codons (CODON, TERMINATOR) that immediately follows the last amino acid-specifying CODON.Peptide Elongation Factor 2: Peptide Elongation Factor 2 catalyzes the translocation of peptidyl-tRNA from the A site to the P site of eukaryotic ribosomes by a process linked to the hydrolysis of GTP to GDP.Gene Expression Profiling: The determination of the pattern of genes expressed at the level of GENETIC TRANSCRIPTION, under specific circumstances or in a specific cell.Methionine: A sulfur-containing essential L-amino acid that is important in many body functions.Cell-Free System: A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)Spiro Compounds: A group of compounds consisting in part of two rings sharing one atom (usually a carbon) in common.Pyridones: Pyridine derivatives with one or more keto groups on the ring.Oligonucleotide Array Sequence Analysis: Hybridization of a nucleic acid sample to a very large set of OLIGONUCLEOTIDE PROBES, which have been attached individually in columns and rows to a solid support, to determine a BASE SEQUENCE, or to detect variations in a gene sequence, GENE EXPRESSION, or for GENE MAPPING.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Peptide Elongation Factor 1: Peptide elongation factor 1 is a multisubunit protein that is responsible for the GTP-dependent binding of aminoacyl-tRNAs to eukaryotic ribosomes. The alpha subunit (EF-1alpha) binds aminoacyl-tRNA and transfers it to the ribosome in a process linked to GTP hydrolysis. The beta and delta subunits (EF-1beta, EF-1delta) are involved in exchanging GDP for GTP. The gamma subunit (EF-1gamma) is a structural component.Leucine-tRNA Ligase: An enzyme that activates leucine with its specific transfer RNA. EC Triphosphate: Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety.Leucine: An essential branched-chain amino acid important for hemoglobin formation.Amino Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Nucleic Acid Conformation: The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.RNA, Bacterial: Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.Streptomyces: A genus of bacteria that form a nonfragmented aerial mycelium. Many species have been identified with some being pathogenic. This genus is responsible for producing a majority of the ANTI-BACTERIAL AGENTS of practical value.Gene Expression Regulation, Plant: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.Molecular Structure: The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.Anticodon: The sequential set of three nucleotides in TRANSFER RNA that interacts with its complement in MESSENGER RNA, the CODON, during translation in the ribosome.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.RNA: A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Puromycin: A cinnamamido ADENOSINE found in STREPTOMYCES alboniger. It inhibits protein synthesis by binding to RNA. It is an antineoplastic and antitrypanosomal agent and is used in research as an inhibitor of protein synthesis.Saccharomyces cerevisiae: A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.Gene Expression Regulation, Bacterial: Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.Carbon Radioisotopes: Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.Reticulocytes: Immature ERYTHROCYTES. In humans, these are ERYTHROID CELLS that have just undergone extrusion of their CELL NUCLEUS. They still contain some organelles that gradually decrease in number as the cells mature. RIBOSOMES are last to disappear. Certain staining techniques cause components of the ribosomes to precipitate into characteristic "reticulum" (not the same as the ENDOPLASMIC RETICULUM), hence the name reticulocytes.Peptide Initiation Factors: Protein factors uniquely required during the initiation phase of protein synthesis in GENETIC TRANSLATION.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.RNA, Ribosomal: The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. (Dorland, 28th ed)TritiumPolyribosomes: A multiribosomal structure representing a linear array of RIBOSOMES held together by messenger RNA; (RNA, MESSENGER); They represent the active complexes in cellular protein synthesis and are able to incorporate amino acids into polypeptides both in vivo and in vitro. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Fungal Proteins: Proteins found in any species of fungus.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Multigene Family: A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.Guanine NucleotidesProteome: The protein complement of an organism coded for by its genome.Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Mass Spectrometry: An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.Guanosine Diphosphate: A guanine nucleotide containing two phosphate groups esterified to the sugar moiety.Genes, Bacterial: The functional hereditary units of BACTERIA.Peptides: Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.DNA, Complementary: Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Reverse Transcriptase Polymerase Chain Reaction: A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.Molecular Weight: The sum of the weight of all the atoms in a molecule.Cell Line: Established cell cultures that have the potential to propagate indefinitely.DNA Primers: Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Genetic Complementation Test: A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Electrophoresis, Gel, Two-Dimensional: Electrophoresis in which a second perpendicular electrophoretic transport is performed on the separate components resulting from the first electrophoresis. This technique is usually performed on polyacrylamide gels.Terpenes: A class of compounds composed of repeating 5-carbon units of HEMITERPENES.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Acyltransferases: Enzymes from the transferase class that catalyze the transfer of acyl groups from donor to acceptor, forming either esters or amides. (From Enzyme Nomenclature 1992) EC 2.3.Polyketide Synthases: Large enzyme complexes composed of a number of component enzymes that are found in STREPTOMYCES which biosynthesize MACROLIDES and other polyketides.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Peptide Synthases: Ligases that catalyze the joining of adjacent AMINO ACIDS by the formation of carbon-nitrogen bonds between their carboxylic acid groups and amine groups.Glucose: A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.Blotting, Northern: Detection of RNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Codon: A set of three nucleotides in a protein coding sequence that specifies individual amino acids or a termination signal (CODON, TERMINATOR). Most codons are universal, but some organisms do not produce the transfer RNAs (RNA, TRANSFER) complementary to all codons. These codons are referred to as unassigned codons (CODONS, NONSENSE).Proteomics: The systematic study of the complete complement of proteins (PROTEOME) of organisms.Protein Structure, Tertiary: The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.Glycosyltransferases: Enzymes that catalyze the transfer of glycosyl groups to an acceptor. Most often another carbohydrate molecule acts as an acceptor, but inorganic phosphate can also act as an acceptor, such as in the case of PHOSPHORYLASES. Some of the enzymes in this group also catalyze hydrolysis, which can be regarded as transfer of a glycosyl group from the donor to water. Subclasses include the HEXOSYLTRANSFERASES; PENTOSYLTRANSFERASES; SIALYLTRANSFERASES; and those transferring other glycosyl groups. EC 2.4.Oxidoreductases: The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)Arabidopsis: A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.Mitochondria: Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)Plant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Nucleic Acid Hybridization: Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Chromatography, Thin Layer: Chromatography on thin layers of adsorbents rather than in columns. The adsorbent can be alumina, silica gel, silicates, charcoals, or cellulose. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Mevalonic AcidDose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Tumor Cells, Cultured: Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.Alkyl and Aryl Transferases: A somewhat heterogeneous class of enzymes that catalyze the transfer of alkyl or related groups (excluding methyl groups). EC 2.5.Cell Division: The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.Genes, Plant: The functional hereditary units of PLANTS.Polyisoprenyl Phosphates: Phosphoric or pyrophosphoric acid esters of polyisoprenoids.Sequence Alignment: The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.Pteridines: Compounds based on pyrazino[2,3-d]pyrimidine which is a pyrimidine fused to a pyrazine, containing four NITROGEN atoms.Methyltransferases: A subclass of enzymes of the transferase class that catalyze the transfer of a methyl group from one compound to another. (Dorland, 28th ed) EC 2.1.1.Arabidopsis Proteins: Proteins that originate from plants species belonging to the genus ARABIDOPSIS. The most intensely studied species of Arabidopsis, Arabidopsis thaliana, is commonly used in laboratory experiments.Carbon Isotopes: Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.Sterols: Steroids with a hydroxyl group at C-3 and most of the skeleton of cholestane. Additional carbon atoms may be present in the side chain. (IUPAC Steroid Nomenclature, 1987)Transferases: Transferases are enzymes transferring a group, for example, the methyl group or a glycosyl group, from one compound (generally regarded as donor) to another compound (generally regarded as acceptor). The classification is based on the scheme "donor:acceptor group transferase". (Enzyme Nomenclature, 1992) EC 2.Lyases: A class of enzymes that catalyze the cleavage of C-C, C-O, and C-N, and other bonds by other means than by hydrolysis or oxidation. (Enzyme Nomenclature, 1992) EC 4.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.HexosaminesPhylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Anthraquinones: Compounds based on ANTHRACENES which contain two KETONES in any position. Substitutions can be in any position except on the ketone groups.Plants, Genetically Modified: PLANTS, or their progeny, whose GENOME has been altered by GENETIC ENGINEERING.Acetates: Derivatives of ACETIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxymethane structure.Erythritol: A four-carbon sugar that is found in algae, fungi, and lichens. It is twice as sweet as sucrose and can be used as a coronary vasodilator.Gene Deletion: A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus.Hemiterpenes: The five-carbon building blocks of TERPENES that derive from MEVALONIC ACID or deoxyxylulose phosphate.Mutagenesis, Insertional: Mutagenesis where the mutation is caused by the introduction of foreign DNA sequences into a gene or extragenic sequence. This may occur spontaneously in vivo or be experimentally induced in vivo or in vitro. Proviral DNA insertions into or adjacent to a cellular proto-oncogene can interrupt GENETIC TRANSLATION of the coding sequences or interfere with recognition of regulatory elements and cause unregulated expression of the proto-oncogene resulting in tumor formation.Cell Wall: The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.Ethylenes: Derivatives of ethylene, a simple organic gas of biological origin with many industrial and biological use.Tetrapyrroles: Four PYRROLES joined by one-carbon units linking position 2 of one to position 5 of the next. The conjugated bond system results in PIGMENTATION.Carbohydrate Sequence: The sequence of carbohydrates within POLYSACCHARIDES; GLYCOPROTEINS; and GLYCOLIPIDS.Fatty Acids: Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)Ergosterol: A steroid of interest both because its biosynthesis in FUNGI is a target of ANTIFUNGAL AGENTS, notably AZOLES, and because when it is present in SKIN of animals, ULTRAVIOLET RAYS break a bond to result in ERGOCALCIFEROL.Multienzyme Complexes: Systems of enzymes which function sequentially by catalyzing consecutive reactions linked by common metabolic intermediates. They may involve simply a transfer of water molecules or hydrogen atoms and may be associated with large supramolecular structures such as MITOCHONDRIA or RIBOSOMES.Siderophores: Low-molecular-weight compounds produced by microorganisms that aid in the transport and sequestration of ferric iron. (The Encyclopedia of Molecular Biology, 1994)Recombinant Proteins: Proteins prepared by recombinant DNA technology.Mixed Function Oxygenases: Widely distributed enzymes that carry out oxidation-reduction reactions in which one atom of the oxygen molecule is incorporated into the organic substrate; the other oxygen atom is reduced and combined with hydrogen ions to form water. They are also known as monooxygenases or hydroxylases. These reactions require two substrates as reductants for each of the two oxygen atoms. There are different classes of monooxygenases depending on the type of hydrogen-providing cosubstrate (COENZYMES) required in the mixed-function oxidation.Coenzymes: Small molecules that are required for the catalytic function of ENZYMES. Many VITAMINS are coenzymes.Plants: Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.Nucleotidyltransferases: A class of enzymes that transfers nucleotidyl residues. EC 2.7.7.Gene Expression Regulation, Enzymologic: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).Peptide Biosynthesis, Nucleic Acid-Independent: The enzymatic synthesis of PEPTIDES without an RNA template by processes that do not use the ribosomal apparatus (RIBOSOMES).Glucosyltransferases: Enzymes that catalyze the transfer of glucose from a nucleoside diphosphate glucose to an acceptor molecule which is frequently another carbohydrate. EC 2.4.1.-.Hydro-Lyases: Enzymes that catalyze the breakage of a carbon-oxygen bond leading to unsaturated products via the removal of water. EC 4.2.1.Plant Leaves: Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)Carotenoids: The general name for a group of fat-soluble pigments found in green, yellow, and leafy vegetables, and yellow fruits. They are aliphatic hydrocarbons consisting of a polyisoprene backbone.Glycolipids: Any compound containing one or more monosaccharide residues bound by a glycosidic linkage to a hydrophobic moiety such as an acylglycerol (see GLYCERIDES), a sphingoid, a ceramide (CERAMIDES) (N-acylsphingoid) or a prenyl phosphate. (From IUPAC's webpage)Farnesyl-Diphosphate Farnesyltransferase: The first committed enzyme of the biosynthesis pathway that leads to the production of STEROLS. it catalyzes the synthesis of SQUALENE from farnesyl pyrophosphate via the intermediate PRESQUALENE PYROPHOSPHATE. This enzyme is also a critical branch point enzyme in the biosynthesis of ISOPRENOIDS that is thought to regulate the flux of isoprene intermediates through the sterol pathway.Culture Media: Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.Cyclopentanes: A group of alicyclic hydrocarbons with the general formula R-C5H9.Carbohydrate Epimerases: Enzymes that catalyze the epimerization of chiral centers within carbohydrates or their derivatives. EC 5.1.3.Lignin: The most abundant natural aromatic organic polymer found in all vascular plants. Lignin together with cellulose and hemicellulose are the major cell wall components of the fibers of all wood and grass species. Lignin is composed of coniferyl, p-coumaryl, and sinapyl alcohols in varying ratios in different plant species. (From Merck Index, 11th ed)Oxidoreductases Acting on CH-CH Group Donors: A subclass of enzymes which includes all dehydrogenases acting on carbon-carbon bonds. This enzyme group includes all the enzymes that introduce double bonds into substrates by direct dehydrogenation of carbon-carbon single bonds.Transaminases: A subclass of enzymes of the transferase class that catalyze the transfer of an amino group from a donor (generally an amino acid) to an acceptor (generally a 2-keto acid). Most of these enzymes are pyridoxyl phosphate proteins. (Dorland, 28th ed) EC 2.6.1.Plant Growth Regulators: Any of the hormones produced naturally in plants and active in controlling growth and other functions. There are three primary classes: auxins, cytokinins, and gibberellins.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Lanosterol: A triterpene that derives from the chair-boat-chair-boat folding of 2,3-oxidosqualene. It is metabolized to CHOLESTEROL and CUCURBITACINS.Carboxy-Lyases: Enzymes that catalyze the addition of a carboxyl group to a compound (carboxylases) or the removal of a carboxyl group from a compound (decarboxylases). EC 4.1.1.Gibberellins: A class of plant growth hormone isolated from cultures of Gibberella fujikuroi, a fungus causing Bakanae disease in rice. There are many different members of the family as well as mixtures of multiple members; all are diterpenoid acids based on the gibberellane skeleton.Uridine Diphosphate N-Acetylglucosamine: Serves as the biological precursor of insect chitin, of muramic acid in bacterial cell walls, and of sialic acids in mammalian glycoproteins.Metabolic Networks and Pathways: Complex sets of enzymatic reactions connected to each other via their product and substrate metabolites.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Glycosylation: The chemical or biochemical addition of carbohydrate or glycosyl groups to other chemicals, especially peptides or proteins. Glycosyl transferases are used in this biochemical reaction.SqualeneMicrosomes: Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Open Reading Frames: A sequence of successive nucleotide triplets that are read as CODONS specifying AMINO ACIDS and begin with an INITIATOR CODON and end with a stop codon (CODON, TERMINATOR).Galactosyltransferases: Enzymes that catalyze the transfer of galactose from a nucleoside diphosphate galactose to an acceptor molecule which is frequently another carbohydrate. EC 2.4.1.-.GlucosamineAlcohol Oxidoreductases: A subclass of enzymes which includes all dehydrogenases acting on primary and secondary alcohols as well as hemiacetals. They are further classified according to the acceptor which can be NAD+ or NADP+ (subclass 1.1.1), cytochrome (1.1.2), oxygen (1.1.3), quinone (1.1.5), or another acceptor (1.1.99).Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Pantothenic Acid: A butyryl-beta-alanine that can also be viewed as pantoic acid complexed with BETA ALANINE. It is incorporated into COENZYME A and protects cells against peroxidative damage by increasing the level of GLUTATHIONE.Plant Roots: The usually underground portions of a plant that serve as support, store food, and through which water and mineral nutrients enter the plant. (From American Heritage Dictionary, 1982; Concise Dictionary of Biology, 1990)Oxylipins: Eighteen-carbon cyclopentyl polyunsaturated fatty acids derived from ALPHA-LINOLENIC ACID via an oxidative pathway analogous to the EICOSANOIDS in animals. Biosynthesis is inhibited by SALICYLATES. A key member, jasmonic acid of PLANTS, plays a similar role to ARACHIDONIC ACID in animals.Operon: In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Seeds: The encapsulated embryos of flowering plants. They are used as is or for animal feed because of the high content of concentrated nutrients like starches, proteins, and fats. Rapeseed, cottonseed, and sunflower seed are also produced for the oils (fats) they yield.Intramolecular Transferases: Enzymes of the isomerase class that catalyze the transfer of acyl-, phospho-, amino- or other groups from one position within a molecule to another. EC 5.4.PolysaccharidesPolyaminesThiamine: 3-((4-Amino-2-methyl-5-pyrimidinyl)methyl)-5-(2- hydroxyethyl)-4-methylthiazolium chloride.Biocatalysis: The facilitation of biochemical reactions with the aid of naturally occurring catalysts such as ENZYMES.Polysaccharides, Bacterial: Polysaccharides found in bacteria and in capsules thereof.

Diphtheria toxin effects on human cells in tissue culture. (1/24808)

HeLa cells exposed to a single sublethal concentration of diphtheria toxin were found to have diminished sensitivity when subsequently reexposed to the toxin. Three cells strains exhibiting toxin resistance were developed. In the cells that had previously been exposed to toxin at 0.015 mug/ml, 50% inhibition of protein synthesis required a toxin concentration of 0.3 mug/ml, which is more than 10 times that required in normal HeLa cells. There appears to be a threshold level of diphtheria toxin action. Concentrations of toxin greater than that required for 50% inhibition of protein synthesis (0.01 mug/ml) are associated with cytotoxicity, whereas those below this concentration may not be lethal. Several established human cell lines of both normal and neoplastic origin were tested for their sensitivity to the effects of the toxin. No special sensitivity was observed with the cells of tumor origin. Fifty % inhibition of protein synthesis of HeLa cells was achieved with diphtheria toxin (0.01 mug/ml) as compared to the normal human cell lines tested (0.03 and 0.5 mug/ml) and a cell line derived from a human pancreatic adenocarcinoma (0.2 mug/ml). A human breast carcinoma cell line showed a maximum of 45% inhibition of protein synthesis. This required a diphtheria toxin concentration of 5 mug/ml. These results suggest that different human cell lines show wide variation in their sensitivity to the toxin.  (+info)

Structural and functional changes in acute liver injury. (2/24808)

Carbon tetrachloride produces liver cell injury in a variety of animal species. The first structurally recognizable changes occur in the endoplasmic reticulum, with alteration in ribosome-membrane interactions. Later there is an increase in intracellular fat, and the formation of tangled nets of the ergastoplasm. At no time are there changes in mitochondria or single membrane limited bodies in cells with intact plasmalemma, although a relative increase in cell sap may appear. In dead cells (those with plasmalemma discontinuties) crystalline deposits of calcium phosphatase may be noted. Functional changes are related to the endoplasmic reticulum and the plasma membrane. An early decrease in protein synthesis takes place; an accumulation of neutral lipid is related to this change. Later alterations in the ergastoplasmic functions (e.g., mixed function oxidation) occurs. Carbon tetrachloride is not the active agent; rather, a product of its metabolism, probably the CC1, free radical, is. The mechanisms of injury include macromolecular adduction and peroxide propagation. A third possibility includes a cascade effect with the production of secondary and tertiary products, also toxic in nature, with the ability to produce more widespread damage to intracellular structures.  (+info)

Apontic binds the translational repressor Bruno and is implicated in regulation of oskar mRNA translation. (3/24808)

The product of the oskar gene directs posterior patterning in the Drosophila oocyte, where it must be deployed specifically at the posterior pole. Proper expression relies on the coordinated localization and translational control of the oskar mRNA. Translational repression prior to localization of the transcript is mediated, in part, by the Bruno protein, which binds to discrete sites in the 3' untranslated region of the oskar mRNA. To begin to understand how Bruno acts in translational repression, we performed a yeast two-hybrid screen to identify Bruno-interacting proteins. One interactor, described here, is the product of the apontic gene. Coimmunoprecipitation experiments lend biochemical support to the idea that Bruno and Apontic proteins physically interact in Drosophila. Genetic experiments using mutants defective in apontic and bruno reveal a functional interaction between these genes. Given this interaction, Apontic is likely to act together with Bruno in translational repression of oskar mRNA. Interestingly, Apontic, like Bruno, is an RNA-binding protein and specifically binds certain regions of the oskar mRNA 3' untranslated region.  (+info)

A Drosophila doublesex-related gene, terra, is involved in somitogenesis in vertebrates. (4/24808)

The Drosophila doublesex (dsx) gene encodes a transcription factor that mediates sex determination. We describe the characterization of a novel zebrafish zinc-finger gene, terra, which contains a DNA binding domain similar to that of the Drosophila dsx gene. However, unlike dsx, terra is transiently expressed in the presomitic mesoderm and newly formed somites. Expression of terra in presomitic mesoderm is restricted to cells that lack expression of MyoD. In vivo, terra expression is reduced by hedgehog but enhanced by BMP signals. Overexpression of terra induces rapid apoptosis both in vitro and in vivo, suggesting that a tight regulation of terra expression is required during embryogenesis. Terra has both human and mouse homologs and is specifically expressed in mouse somites. Taken together, our findings suggest that terra is a highly conserved protein that plays specific roles in early somitogenesis of vertebrates.  (+info)

High-throughput screening of small molecules in miniaturized mammalian cell-based assays involving post-translational modifications. (5/24808)

BACKGROUND: Fully adapting a forward genetic approach to mammalian systems requires efficient methods to alter systematically gene products without prior knowledge of gene sequences, while allowing for the subsequent characterization of these alterations. Ideally, these methods would also allow function to be altered in a temporally controlled manner. RESULTS: We report the development of a miniaturized cell-based assay format that enables a genetic-like approach to understanding cellular pathways in mammalian systems using small molecules, rather than mutations, as the source of gene-product alterations. This whole-cell immunodetection assay can sensitively detect changes in specific cellular macromolecules in high-density arrays of mammalian cells. Furthermore, it is compatible with screening large numbers of small molecules in nanoliter to microliter culture volumes. We refer to this assay format as a 'cytoblot', and demonstrate the use of cytoblotting to monitor biosynthetic processes such as DNA synthesis, and post-translational processes such as acetylation and phosphorylation. Finally, we demonstrate the applicability of these assays to natural-product screening through the identification of marine sponge extracts exhibiting genotype-specific inhibition of 5-bromodeoxyuridine incorporation and suppression of the anti-proliferative effect of rapamycin. CONCLUSIONS: We show that cytoblots can be used for high-throughput screening of small molecules in cell-based assays. Together with small-molecule libraries, the cytoblot assay can be used to perform chemical genetic screens analogous to those used in classical genetics and thus should be applicable to understanding a wide variety of cellular processes, especially those involving post-transitional modifications.  (+info)

Telomerase reverse transcriptase gene is a direct target of c-Myc but is not functionally equivalent in cellular transformation. (6/24808)

The telomerase reverse transcriptase component (TERT) is not expressed in most primary somatic human cells and tissues, but is upregulated in the majority of immortalized cell lines and tumors. Here, we identify the c-Myc transcription factor as a direct mediator of telomerase activation in primary human fibroblasts through its ability to specifically induce TERT gene expression. Through the use of a hormone inducible form of c-Myc (c-Myc-ER), we demonstrate that Myc-induced activation of the hTERT promoter requires an evolutionarily conserved E-box and that c-Myc-ER-induced accumulation of hTERT mRNA takes place in the absence of de novo protein synthesis. These findings demonstrate that the TERT gene is a direct transcriptional target of c-Myc. Since telomerase activation frequently correlates with immortalization and telomerase functions to stabilize telomers in cycling cells, we tested whether Myc-induced activation of TERT gene expression represents an important mechanism through which c-Myc acts to immortalize cells. Employing the rat embryo fibroblast cooperation assay, we show that TERT is unable to substitute for c-Myc in the transformation of primary rodent fibroblasts, suggesting that the transforming activities of Myc extend beyond its ability to activate TERT gene expression and hence telomerase activity.  (+info)

C/EBPalpha regulates generation of C/EBPbeta isoforms through activation of specific proteolytic cleavage. (7/24808)

C/EBPalpha and C/EBPbeta are intronless genes that can produce several N-terminally truncated isoforms through the process of alternative translation initiation at downstream AUG codons. C/EBPbeta has been reported to produce four isoforms: full-length 38-kDa C/EBPbeta, 35-kDa LAP (liver-enriched transcriptional activator protein), 21-kDa LIP (liver-enriched transcriptional inhibitory protein), and a 14-kDa isoform. In this report, we investigated the mechanisms by which C/EBPbeta isoforms are generated in the liver and in cultured cells. Using an in vitro translation system, we found that LIP can be generated by two mechanisms: alternative translation and a novel mechanism-specific proteolytic cleavage of full-length C/EBPbeta. Studies of mice in which the C/EBPalpha gene had been deleted (C/EBPalpha-/-) showed that the regulation of C/EBPbeta proteolysis is dependent on C/EBPalpha. The induction of C/EBPalpha in cultured cells leads to induced cleavage of C/EBPbeta to generate the LIP isoform. We characterized the cleavage activity in mouse liver extracts and found that the proteolytic cleavage activity is specific to prenatal and newborn livers, is sensitive to chymostatin, and is completely abolished in C/EBPalpha-/- animals. The lack of cleavage activity in the livers of C/EBPalpha-/- mice correlates with the decreased levels of LIP in the livers of these animals. Analysis of LIP production during liver regeneration showed that, in this system, the transient induction of LIP is dependent on the third AUG codon and most likely involves translational control. We propose that there are two mechanisms by which C/EBPbeta isoforms might be generated in the liver and in cultured cells: one that is determined by translation and a second that involves C/EBPalpha-dependent, specific proteolytic cleavage of full-length C/EBPbeta. The latter mechanism implicates C/EBPalpha in the regulation of posttranslational generation of the dominant negative C/EBPbeta isoform, LIP.  (+info)

Phosphorylation of the cap-binding protein eukaryotic translation initiation factor 4E by protein kinase Mnk1 in vivo. (8/24808)

Eukaryotic translation initiation factor 4E (eIF4E) binds to the mRNA 5' cap and brings the mRNA into a complex with other protein synthesis initiation factors and ribosomes. The activity of mammalian eIF4E is important for the translation of capped mRNAs and is thought to be regulated by two mechanisms. First, eIF4E is sequestered by binding proteins, such as 4EBP1, in quiescent cells. Mitogens induce the release of eIF4E by stimulating the phosphorylation of 4EBP1. Second, mitogens and stresses induce the phosphorylation of eIF4E at Ser 209, increasing the affinity of eIF4E for capped mRNA and for an associated scaffolding protein, eIF4G. We previously showed that a mitogen- and stress-activated kinase, Mnk1, phosphorylates eIF4E in vitro at the physiological site. Here we show that Mnk1 regulates eIF4E phosphorylation in vivo. Mnk1 binds directly to eIF4G and copurifies with eIF4G and eIF4E. We identified activating phosphorylation sites in Mnk1 and developed dominant-negative and activated mutants. Expression of dominant-negative Mnk1 reduces mitogen-induced eIF4E phosphorylation, while expression of activated Mnk1 increases basal eIF4E phosphorylation. Activated mutant Mnk1 also induces extensive phosphorylation of eIF4E in cells overexpressing 4EBP1. This suggests that phosphorylation of eIF4E is catalyzed by Mnk1 or a very similar kinase in cells and is independent of other mitogenic signals that release eIF4E from 4EBP1.  (+info)

  • In this article, we have demonstrated that the major retrograde signaling protein GUN1 can bind tetrapyrroles and regulate the flow through the tetrapyrrole biosynthesis pathway. (
  • In animals, the de novo pathway is initiated and controlled by CAD, a ∼240‐kDa multifunctional protein with four different enzymatic domains: glutaminase (GLN), carbamoyl phosphate synthetase (CPS), dihydroorotase (DHO) and aspartate transcarbamoylase (ATC). (
  • a) Overview of the de novo pathway for the biosynthesis of pyrimidines. (
  • Thus, Fd1, a one-electron carrier protein in photosynthesis, drives the phycobilin biosynthetic pathway. (
  • Functional enrichment and pathway analysis revealed that four pathways might be involved in storage protein biosynthesis. (
  • The bacterial fatty acid biosynthesis (FASII) pathway is a promising target for antibacterial drug discovery and current research is focused on elucidating the substrate specificity of the b-ketoacyl-ACP synthase (KAS) enzymes in this pathway, identify the interactions between the components of the FASII pathway and discovering the unknown dehydratase, and studying the interaction of current enzyme inhibitors with FASII components in whole cells. (
  • Several data in the literature suggest the existence of protein-protein interactions within the FASII pathway. (
  • This disaggregase accumulates when the MEP pathway flux is decreased and in situations causing protein folding stress. (
  • E)-4-hydroxy-3-methylbut-2-enyl diphosphate synthase (GcpE or IspG) and (E)-4-hydroxy-3-methylbut-2-enyl diphosphate reductase (LytB or IspH) are involved in the last two steps of the DOXP pathway for isoprenoid biosynthesis. (
  • The evolutionary conservation of the complex diphthamide biosynthesis pathway throughout eukaryotes implies a key role for diphthamide in normal cellular physiology. (
  • This hypothesis is supported by evidence that inhibition of the TOR (target of rapamycin) pathway and various translation factors that inhibit protein synthesis lead to slowing of growth and development but extend lifespan. (
  • Here, we report that increased synthesis of N-glycan precursors in the hexosamine pathway improves ER protein homeostasis and extends lifespan in C. elegans. (
  • A role for SP85 and interacting coat proteins in this signaling pathway explains many of the defects of SP85-null spores and the dominant negative effects of the partial length fragments. (
  • Eukaryotes usually have two separate enzymes, while most prokaryotes have a single bifunctional protein that can carry out both catalyses, although exceptions occur in both cases. (
  • Members of this family are members of the superfamily of activating enzymes (E1) of the ubiquitin-like proteins [ PMID: 12660720 ]. (
  • To express a protein by a cell-free system, purified and separated components from cell lysates, e.g. of prokaryotic or eucaryotic origin, get re-combined with certain additives (e.g. amino acids, energy or buffer components, transcription enzymes) in a test tube in a respective manner to process a complete bio-protein synthetic cycle of an offered gene, which encodes for a certain protein. (
  • Biosynthesis of lanthionine-constrained peptides exploiting engineered Gram-positive or Gram-negative bacteria that contain lanthionine-introducing enzymes constitutes a convenient method for discovery of lanthionine-stabilized GPCR agonists. (
  • The two committed enzymatic steps of riboflavin biosynthesis are performed in plants by bifunctional RIBA enzymes comprised of GTP cyclohydrolase II (GCHII) and 3,4-dihydroxy-2-butanone-4-phosphate synthase (DHBPS). (
  • Transcription of miRNA-encoding genes is catalyzed by RNA polymerase II, and the transcripts are spliced into mature miRNA via dicer-like enzymes and several protein complexes ( Bartel, 2004 ). (
  • Ergosterol is a major and specific component of the fungal plasma membrane, and thus, the cytochrome P450 enzymes (Erg proteins) that catalyze ergosterol synthesis have been selected as valuable targets of azole antifungals. (
  • In this study, we demonstrate that a cytochrome b 5 -like heme-binding damage resistance protein (Dap) family, comprised of DapA, DapB, and DapC, coordinately regulates the functionality of cytochrome P450 enzymes Erg5 and Erg11 and oppositely affects susceptibility to azoles. (
  • The AdrA protein can catalyze the synthesis of bis-(3′,5′)-cyclic diguanylic acid (cyclic di-GMP), which in turn stimulates the enzymes responsible for cellulose production ( 48 ). (
  • Substrates are shuttled between the FASII enzymes by acyl carrier protein, a phosphopantetheinylated protein with a MW of 13 kDa in Mycobacterium tuberculosis and 7 kDa in Escherichia coli. (
  • All systems, however, construct Fe-S clusters through a similar biosynthetic scheme involving three main steps: (1) sulfur activation by a cysteine desulfurase, (2) cluster assembly by a scaffold protein, and (3) guided delivery of Fe-S units to either final acceptors or biosynthetic enzymes involved in the formation of complex metalloclusters. (
  • Furthermore, we analyzed the thioester reductase FclG and the free-standing condensation domain-like protein FclL in detail and observed low substrate specificity for both enzymes. (
  • Phosphoproteome analysis of functional mitochondria isolated from resting human muscle reveals extensive phosphorylation of inner membrane protein complexes and enzymes. (
  • Transcription can be divided into 3 stages: initiation, elongation, and termination, each regulated by a large number of proteins such as transcription factors and coactivators that ensure that the correct gene is transcribed. (
  • A gene on chromosome 2q35 that encodes a bifunctional protein that catalyses the last two steps in purine biosynthesis. (
  • The gene‐specific translation initiation region (TIR) drives a growth‐dependent, differential production of proteins in the absence of regulators. (
  • Given its critical importance as the ultimate step in gene expression and its significant energy requirements, the fidelity and efficiency of protein synthesis are key elements for cell growth and development. (
  • A gene on chromosome 17p13.2 that encodes a component of the glycosylphosphatidylinositol (GPI) transamidase complex essential for the transfer of GPI to proteins and involved in GPI-anchor and glycolipid biosynthesis. (
  • Our results indicate that CsgD can modulate cellulose biosynthesis through activation of the yoaD gene. (
  • Expression of both curli and cellulose depends on the CsgD protein, a putative transcription regulator of the LuxR family, which activates transcription of the csgBAC operon ( 2 ), which encodes curli structural subunits, and transcription of the adrA gene, a positive effector of cellulose biosynthesis ( 45 ). (
  • The product of the CsgD-dependent adrA gene is a member of the GGDEF protein family ( 16 , 50 ). (
  • Our data therefore confirm that GUN1 is a central integrator of different pathways controlling chloroplast protein homeostasis beyond the control of nuclear gene ex- pression. (
  • If a protein contains two or more different polypeptide chains, each chain is coded by a different gene. (
  • This locus represents a mitochondrial ubiquinone biosynthesis gene. (
  • literature review doctoral dissertation chapters neoa, b, and c social legal and ethical issues in counselling essays of elia encoded in the butirosin and neomycin biosynthesis of proteins neomycin biosynthetic gene cluster have been enzymatically confirmed to be responsible to the formation of 2-deoxystreptamine learning to read and write thesis (dos) essay about my village in malaysia children in streptomyces fradiae. (
  • Increased Alix (apoptosis-linked gene-2 interacting protein X) immunoreactivity in the degenerating striatum of rats chronically treated by 3-nitropropionic acid. (
  • The sequence of amino acid residues in a protein is defined by the sequence of a gene , which is encoded in the genetic code . (
  • In this study, we characterized two noncatalytic chalcone isomerase (CHI)-like proteins (designated as HlCHIL1 and HlCHIL2) using engineered yeast harboring all genes required for DMX production. (
  • sad1 plants are also defective in the positive feedback regulation of ABA biosynthesis genes by ABA and are impaired in drought stress induction of ABA biosynthesis. (
  • Among these genes are yloU and yqhY which encode the paralogous proteins YloU and YqhY. (
  • In summary, our findings suggest that drought stress may enhance storage protein by regulating the expression of miRNAs and their target genes. (
  • The expression of all three genes is induced in an azole concentration-dependent way, and the decreased susceptibility to azoles requires DapA stabilization of cytochrome P450 protein activity. (
  • Constitutive expression of the CsgD protein results in altered transcription patterns for at least 24 novel genes, in addition to the previously identified CsgD-dependent genes. (
  • The cspA and fecR genes, encoding regulatory proteins responding to cold shock and to iron, respectively, and yoaD , encoding a putative negative regulator of cellulose biosynthesis, were found to be some of the novel CsgD-regulated genes. (
  • The Pseudomonas aeruginosa fabA and fabB genes, encoding beta-hydroxyacyl-acyl carrier protein dehydratase and beta-ketoacyl-acyl carrier protein synthase I, respectively, were cloned, sequenced, and expressed in Escherichia coli. (
  • As with other positive activator proteins, when pyrimidine nucleotides are depleted, PyrR binds to DNA thereby enhancing expression of pyrD, pyrE and pyrF genes. (
  • We elucidated the biosynthesis of these NRPS-PKS hybrids in Xenorhabdus szentirmaii by deletion of most genes encoded in the fabclavine BGC and subsequent analysis of produced fabclavine or polyamine intermediates. (
  • Elicitation of this cpUPR by inhibition of protein synthesis in the chloroplast led to increased expression of nuclear genes encoding ClpB3 and other chloroplast chap- erones, eventually causing a stress acclimation response. (
  • We found 394 GPA1-regulated genes spanning 79 biological processes, including biotic and abiotic stresses, development, flavonoid biosynthesis, transcription factors, transporters and nitrate/phosphate responses. (
  • Here, we show in Pisum sativum L. that the DELLA proteins can activate the expression of KNOX and BELL transcription factors involved in regulation of cytokinin metabolic and response genes. (
  • The plural is used here because, with most genes, the splicing process produces more than one final working protein. (
  • Antigen presentation occurs when degradation products of protein antigens become attached to molecules encoded by a group of genes called the Major Histocompatibility Complex (MHC) and displayed on cell surfaces. (
  • Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes , and which usually results in protein folding into a specific three-dimensional structure that determines its activity. (
  • We isolated a knock-out mutant of the Arabidopsis G-protein α subunit (gpa1-5) and analysed its transcriptome to understand the genomewide role of GPA1 and compared it with that of our similar analysis of a GCR1 mutant (Chakraborty et al. (
  • The Arabidopsis mutant (FLU), unable to control biosynthesis of protochlorophyllide, glows red in the blue light. (
  • The second part of the thesis continued previous work with DXI1, a DXS-interacting J-protein that facilitates the recognition of inactive DXS forms to deliver them to eventual reactivation or degradation pathways. (
  • A collection of articles that focus on an array of different scientific topics such as pathways, cancer, transmembrane proteins. (
  • We will discuss the molecular players (RNA binding proteins and neuronal mRNAs), the signal transduction pathways that have been implicated in learning and memory and how localized translation of selected mRNAs is involved in synaptic plasticity. (
  • Involved in the biosynthesis of the antibiotic phenazine, a nitrogen-containing heterocyclic molecule having important roles in virulence, competition and biological control. (
  • and polymyxin german egyptian research long-term scholarship essay b (topical route) antibiotic otic - neomycin, polymyxin b, and hydrocortisone (otic butirosin and neomycin biosynthesis of proteins route) anticholinergics and antispasmodics (oral route. (
  • The affinity of BlaC for the inhibitors was further studied using catalytically inactive mutants of the enzyme.In parallel, the Alr and YlmE proteins from S. coelicolor A3(2) were studied. (
  • Later, by the sequence similarity, a similar protein was found in Chlamydomonas algae, showing that this regulatory subsystem existed a long time before the angiosperms lost the independent conversion enzyme. (
  • Central to FA synthesis, the ACP (acyl carrier protein) represents the cofactor protein that covalently binds all fatty acyl intermediates via a phosphopantetheine linker during the synthesis process. (
  • Efforts we employed toward characterizing this noncovalent complex include the development of a photoprobe by attaching a benzophenone group to the prosthetic PPant arm of AcpM (B4M-AcpM), the development of a bioorthogonal w-azido fatty acid probe to determine fatty acylated proteins in the cell and lastly, the incorporation of fluorescent tags into InhA in order to quantitate an interaction to KasA. (
  • However, future optimizations of this method along with the incorporation of w-azido fatty acids into cells and the appropriate position to insert fluorescent probes into InhA are required to definitely identify physiologically relevant protein-protein interactions. (
  • Collectively, our data indicate that PLP2 is an integral component of the plant cell death execution machinery, possibly providing fatty acid precursors for the biosynthesis of specific oxylipins and differentially affecting resistance to pathogens with distinct lifestyles. (
  • L. An initial pH of the medium in the range 4.0-7.0 have no significant effect on the protein (38.5-41.3 g/100 g d.w. ), lipid (10.2-12.7 g/100 g d.w. ), or carotenoid (191.7-202.9 μg/g d.w. ) content in the biomass, or on the profile of synthesized fatty acids and carotenoids. (
  • Curli production is dependent on the CsgD transcription activator, which also promotes cellulose biosynthesis. (
  • Expression of curli is linked to cellulose biosynthesis, which leads to the production of an extracellular matrix and results in tight cell-cell and cell-surface interactions and in the so-called rdar morphotype in Salmonella ( 45 , 57 , 58 ). (
  • Incorporation of nonnatural amino acid residues allows engineering of proteins with novel chemical functionality and unusual physical properties. (
  • Furthermore, the coiled-coil protein used to demonstrate incorporation of 2 exhibits enhanced stability in comparison to the same protein enriched in 1, possibly due to the increased hydrophobic character of the additional trifluoromethyl group in the protein core. (
  • The incorporation of Tcg into proteins creates new opportunities for macromolecular synthesis through genetic engineering, due to the rich chemistry of the olefinic side chain. (
  • This high degree of specificity is vital to the incorporation of the correct amino acid into a protein. (
  • IMPORTANCE Knowledge of the ergosterol biosynthesis route in fungal pathogens is useful in the design of new antifungal drugs and could aid in the study of antifungal-drug resistance mechanisms. (
  • During humoral immune responses, proteins called antibodies, which can bind to and destroy pathogens, are secreted into the blood and other body fluids. (
  • Thus, the extensive structural data now available is facilitating the development of chemical and genetic tools to manipulate ABA biosynthesis and signaling and has refined our understanding of these new druggable target sites. (
  • Through molecular, genetic and pharmacological approaches, we demonstrated that this accumulation depends on a mechanism called chloroplast Unfolded Protein Response (cpUPR). (
  • Overall, we validate some known and report many hitherto unknown roles of GPA1 in plants, including agronomically important ones such as biotic stress and nutrient response, and also provide compelling genetic evidence to revisit the role of GCR1 in G-protein signalling. (
  • Here it is proposed that changes in protein synthesis mediate the tradeoffs that take place upon genetic and environmental manipulation in various model systems including yeast, worms, flies and mice. (
  • In this study, we first transfected HEK293 cells with EGFP-DCNP1 and demonstrated that the full-length DCNP1 protein was localized in the nucleus, and RRK (the residues 117-119) composed its nuclear localization signal (NLS). (
  • Consequently, the N-terminus of the trp(G.D) fusion protein is 43 residues shorter than previously postulated. (
  • Of the proteins required for diphthamide synthesis, Dph3 is the smallest, containing only 82 residues. (
  • Arrival of PHA in the protein bodies is followed by the slow removal of these terminal N-acetylglucosamine residues, resulting in a decrease in the Mr of the modified sidechains. (
  • The C-terminal domain of SP85, 197 amino acids, is separated from the remainder of the protein by a series of 10 TXPP tetrapeptide repeats (Fig. ). It consists of a Cys-rich C1 region of 118 amino acids and a C2 region of 79 amino acids that lacks Cys residues. (
  • Proteins ( / ˈ p r oʊ ˌ t iː n z / or / ˈ p r oʊ t i . ɪ n z / ) are large biomolecules , or macromolecules , consisting of one or more long chains of amino acid residues . (
  • Shortly after or even during synthesis, the residues in a protein are often chemically modified by post-translational modification , which alters the physical and chemical properties, folding, stability, activity, and ultimately, the function of the proteins. (
  • Pyrimidines are essential precursors for DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) synthesis, protein glycosylation and lipid synthesis. (
  • Cell-free expression systems in combination with nanodiscs (discoidal lipid bilayer particles) offer a valuable approach to probe membrane proteins in situ. (
  • Customization of the system and offering of a lipid support (here: nanodiscs) enable membrane protein expression in a high yield. (
  • Given that CETP inhibitors are lipid soluble, accumulate in adipose tissue, and have binding sites for proteins involved in adipogenesis, and that adipocytes are a source of aldosterone, we questioned whether CETP inhibitors (torcetrapib, dalcetrapib, and anacetrapib) influence aldosterone production by adipocytes. (
  • This paper reports the study on determination of the effect of initial culture medium pH on growth and protein, lipid and carotenoid biosynthesis by R. glutinis yeast. (
  • The different values of initial pH of the culture medium with glycerol and deproteinized potato wastewater had a significant effect on the growth and on protein, lipid and carotenoid biosynthesis by R. glutinis yeast. (
  • Lipid-binding protein involved in the biosynthesis of coenzyme Q, also named ubiquinone, an essential lipid-soluble electron transporter for aerobic cellular respiration. (
  • This mix of known and putative ThiF proteins shows a deep split in phylogenetic trees. (
  • Phylogenetic analyses imply that the monofunctional, bipartite RIBA3 proteins, which have lost DHBPS activity, evolved early in tracheophyte evolution. (
  • 1818042, ' view Inhibitors of Protein ': ' A Western occupation with this study state only means. (
  • The allosteric activators and inhibitors for the different proteins are shown in blue and red, respectively. (
  • We unite these structural insights with progress in the development of ABA biosynthesis and signaling modulators and cover both inhibitors of 9-cis-expoycarotenoid dioxygenases (NCEDs) and ABA receptor modulators including the agonist quinabactin and antagonist AS6. (
  • We show that CHIL2 is part of an active DMX biosynthetic metabolon in hop glandular trichomes that encompasses a chalcone synthase (CHS) and a membrane-bound prenyltransferase, and that type IV CHI-fold proteins of representative land plants contain conserved function to bind with CHS and enhance its activity. (
  • TolC protein family members are the outer-membrane components of several transport systems involved in the export of diverse molecules, playing an important role in bacterial survival. (
  • Sterols are major components of most eukaryotic plasma membranes and have been shown to be responsible for a number of biological functions, such as membrane fluidity and the functions of integral membrane proteins ( 1 - 6 ). (
  • We found that despite its function as a transcription activator, the CsgD protein is localized in the cytoplasmic membrane. (
  • Crystal structure of a human membrane protein involved in cysteinyl leukotriene biosynthesis. (
  • Ago H, Kanaoka Y, Irikura D, Lam BK, Shimamura T, Austen KF, Miyano M. Crystal structure of a human membrane protein involved in cysteinyl leukotriene biosynthesis. (
  • The regulatory protein is a transmembrane protein that is located in the thylakoid membrane. (
  • The endoplasmic reticulum (ER) is the site of protein synthesis and maturation for secreted and membrane proteins. (
  • Signal sequence and keyword trap in silico for selection of full-length human cDNAs encoding secretion or membrane proteins from oligo-capped cDNA libraries. (
  • p>When browsing through different UniProt proteins, you can use the 'basket' to save them, so that you can back to find or analyse them later. (
  • Immunodetection experiments and comparison of the extracellular proteins present in the supernatant of the wild-type versus tolC mutant strains showed that the calcium-binding protein ExpE1, the endoglycanase ExsH, and the product of open reading frame SMc04171, a putative hemolysin-type calcium-binding protein, are secreted by a TolC-dependent secretion system. (
  • Taken together, our results confirm the importance of TolC in protein secretion, exopolysaccharide biosynthesis, antimicrobials resistance, and symbiosis. (
  • The yeast protein expression system is the most economical and efficient eukaryotic system for secretion and intracellular expression. (
  • View conserved domains detected in this protein sequence using CD-search. (
  • 2. The amino acid sequence may be altered during protein synthesis. (
  • Note that the 'protein existence' evidence does not give information on the accuracy or correctness of the sequence(s) displayed. (
  • Sequence analysis of six mutant alleles has identified base changes producing truncations or single amino acid changes in the TTG1 protein. (
  • Amino acid composition and sequence analyses of the protein products of T.maritima trpC (indoleglycerol phosphate synthase), trpF (phosphoribosyl anthranilate isomerase) and trpA (alpha-subunit of tryptophan synthase) suggest that these thermostable (beta alpha)8-barrel proteins may be stabilized by additional salt bridges, compared with the mesostable forms. (
  • How can a molecule containing just 4 different nucleotides specify the sequence of the 20 amino acids that occur in proteins? (
  • The dark-operative version is a completely different protein, consisting of three subunits that exhibit significant sequence similarity to the three subunits of nitrogenase , which catalyzes the formation of ammonia from dinitrogen. (
  • Proteins perform a vast array of functions within organisms , including catalysing metabolic reactions , DNA replication , responding to stimuli , and transporting molecules from one location to another. (
  • Protein biosynthesis, although very similar, is different for prokaryotes and eukaryotes. (
  • Protein biosynthesis differs between prokaryotes and eukaryotes , though parts of the process are the same in both. (
  • Brachmann AO, Joyce SA, Jenke-Kodama H, Schwär G, Clarke DJ, Bode HB (2007) A type II polyketide synthase is responsible for anthraquinone biosynthesis in Photorhabdus luminescens . (
  • Keating TA, Marshall CG, Walsh CT (2000) Vibriobactin biosynthesis in Vibrio cholerae VibH is an amide synthase homologous to nonribosomal peptide synthetase condensation domains. (
  • Research in this section is focused on understanding translational regulatory mechanisms and the molecular details of protein synthesis in eukaryotic cells. (
  • Please inquire if you are interested in this recombinant protein expressed in E. coli, mammalien cells or by baculovirus infection. (
  • The polypeptides of PHA are synthesized by endoplasmic reticulum-bound polysomes and co-translationally glycosylated, pass through the Golgi complex, and accumulate in protein bodies, which constitute the lysosomal compartment in these cells. (
  • These results indicate that the sorting-signals and posttranslational processing steps for proteins that are transported to the lysosomal compartment are different in plant cells and animal cells. (
  • An alternative approach to express C1 and C2 alone has thus far been unsuccessful in vegetative cells, with most protein remaining intracellular and insoluble in extracts (P. Zhang and C. M. West, unpublished data). (
  • Protein biosynthesis ( synthesis ) is when cells build proteins . (
  • the cytoplasmic ribosomes found in animal cells (80s) are beadle and tatum s hypothesis plural ct appellate court assignment of case search structurally distinct from those found in bacterial cells (70s), making protein biosynthesis a good selective target for antibacterial drugs. (
  • Members of the HesA/MoeB/ThiF family of proteins ( IPR000594 ) include a number of members encoded in the midst of thiamine biosynthetic operons. (
  • Thus, the formation of transient protein complexes among biosynthetic components allows for the direct transfer of reactive sulfur and Fe-S intermediates preventing oxygen damage and reactions with non-physiological targets. (
  • If you cannot find the target and/or product is not available in our catalog, please click here to contact us and request the product or submit your request for custom elisa kit production , custom recombinant protein production or custom antibody production . (
  • The encoded protein is likely necessary for biosynthesis of coenzyme Q10, as mutations at this locus have been associated with autosomal-recessive neonatal-onset primary coenzyme Q10 deficiency. (
  • Sulphur availability is essential for the biosynthesis of the main wheat storage proteins. (
  • Antisense- or RNAi-mediated suppression of the biosynthesis of nutritionally inferior storage proteins is a promising strategy for improving the amino acid profile of seeds. (
  • The results of the transcriptome analysis showed excellent correlation with data on changes in the relative proportions of storage proteins and amino acid composition. (