Serum Response Factor: A MADS domain-containing transcription factor that binds to the SERUM RESPONSE ELEMENT in the promoter-enhancer region of many genes. It is one of the four founder proteins that structurally define the superfamily of MADS DOMAIN PROTEINS.Serum Response Element: A DNA sequence that is found in the promoter region of many growth-related genes. The regulatory transcription factor SERUM RESPONSE FACTOR binds to and regulates the activity of genes containing this element.Response Elements: Nucleotide sequences, usually upstream, which are recognized by specific regulatory transcription factors, thereby causing gene response to various regulatory agents. These elements may be found in both promoter and enhancer regions.ets-Domain Protein Elk-1: A member of the ternary complex family of ets-related transcription factors that is regulated by MITOGEN-ACTIVATED PROTEIN KINASES including JNK MITOGEN-ACTIVATED PROTEIN KINASES; MITOGEN-ACTIVATED PROTEIN KINASE 1; MITOGEN-ACTIVATED PROTEIN KINASE 3; and P38 MITOGEN-ACTIVATED PROTEIN KINASES.Genes, fos: Retrovirus-associated DNA sequences (fos) originally isolated from the Finkel-Biskis-Jinkins (FBJ-MSV) and Finkel-Biskis-Reilly (FBR-MSV) murine sarcoma viruses. The proto-oncogene protein c-fos codes for a nuclear protein which is involved in growth-related transcriptional control. The insertion of c-fos into FBJ-MSV or FBR-MSV induces osteogenic sarcomas in mice. The human c-fos gene is located at 14q21-31 on the long arm of chromosome 14.Proto-Oncogene Proteins c-fos: Cellular DNA-binding proteins encoded by the c-fos genes (GENES, FOS). They are involved in growth-related transcriptional control. c-fos combines with c-jun (PROTO-ONCOGENE PROTEINS C-JUN) to form a c-fos/c-jun heterodimer (TRANSCRIPTION FACTOR AP-1) that binds to the TRE (TPA-responsive element) in promoters of certain genes.Promoter Regions, Genetic: DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.DNA-Binding Proteins: Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.Nuclear Proteins: Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.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.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.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.Early Growth Response Protein 1: An early growth response transcription factor that has been implicated in regulation of CELL PROLIFERATION and APOPTOSIS.ets-Domain Protein Elk-4: A member of the ternary complex family of ets-related transcription factors that is regulated by MITOGEN-ACTIVATED PROTEIN KINASES such as EXTRACELLULAR SIGNAL-REGULATED MAP KINASES; and P38 MITOGEN-ACTIVATED PROTEIN KINASES.Transcriptional Activation: Processes that stimulate the GENETIC TRANSCRIPTION of a gene or set of genes.Regulatory Sequences, Nucleic Acid: Nucleic acid sequences involved in regulating the expression of genes.3T3 Cells: Cell lines whose original growing procedure consisted being transferred (T) every 3 days and plated at 300,000 cells per plate (J Cell Biol 17:299-313, 1963). Lines have been developed using several different strains of mice. Tissues are usually fibroblasts derived from mouse embryos but other types and sources have been developed as well. The 3T3 lines are valuable in vitro host systems for oncogenic virus transformation studies, since 3T3 cells possess a high sensitivity to CONTACT INHIBITION.Transfection: The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.Enhancer Elements, Genetic: Cis-acting DNA sequences which can increase transcription of genes. Enhancers can usually function in either orientation and at various distances from a promoter.Proto-Oncogene Proteins: Products of proto-oncogenes. Normally they do not have oncogenic or transforming properties, but are involved in the regulation or differentiation of cell growth. They often have protein kinase activity.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Genes, Reporter: Genes whose expression is easily detectable and therefore used to study promoter activity at many positions in a target genome. In recombinant DNA technology, these genes may be attached to a promoter region of interest.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Cell Line: Established cell cultures that have the potential to propagate indefinitely.Luciferases: Enzymes that oxidize certain LUMINESCENT AGENTS to emit light (PHYSICAL LUMINESCENCE). The luciferases from different organisms have evolved differently so have different structures and substrates.Chloramphenicol O-Acetyltransferase: An enzyme that catalyzes the acetylation of chloramphenicol to yield chloramphenicol 3-acetate. Since chloramphenicol 3-acetate does not bind to bacterial ribosomes and is not an inhibitor of peptidyltransferase, the enzyme is responsible for the naturally occurring chloramphenicol resistance in bacteria. The enzyme, for which variants are known, is found in both gram-negative and gram-positive bacteria. EC 220.127.116.11.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.Immediate-Early Proteins: Proteins that are coded by immediate-early genes, in the absence of de novo protein synthesis. The term was originally used exclusively for viral regulatory proteins that were synthesized just after viral integration into the host cell. It is also used to describe cellular proteins which are synthesized immediately after the resting cell is stimulated by extracellular signals.Serum: The clear portion of BLOOD that is left after BLOOD COAGULATION to remove BLOOD CELLS and clotting proteins.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.Proto-Oncogenes: Normal cellular genes homologous to viral oncogenes. The products of proto-oncogenes are important regulators of biological processes and appear to be involved in the events that serve to maintain the ordered procession through the cell cycle. Proto-oncogenes have names of the form c-onc.Proto-Oncogene Proteins c-ets: A family of transcription factors that share a unique DNA-binding domain. The name derives from viral oncogene-derived protein oncogene protein v-ets of the AVIAN ERYTHROBLASTOSIS VIRUS.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.Blood Physiological Phenomena: Physiological processes and properties of the BLOOD.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.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.HeLa Cells: The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.Oligodeoxyribonucleotides: A group of deoxyribonucleotides (up to 12) in which the phosphate residues of each deoxyribonucleotide act as bridges in forming diester linkages between the deoxyribose moieties.Fusion Proteins, gag-onc: General name for the translation products of a fusion mRNA consisting of a gag gene and a viral oncogene (v-onc). These products are thought to have the ability to transform cells.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.Cyclic AMP Response Element-Binding Protein: A protein that has been shown to function as a calcium-regulated transcription factor as well as a substrate for depolarization-activated CALCIUM-CALMODULIN-DEPENDENT PROTEIN KINASES. This protein functions to integrate both calcium and cAMP signals.Calcium-Calmodulin-Dependent Protein Kinases: A CALMODULIN-dependent enzyme that catalyzes the phosphorylation of proteins. This enzyme is also sometimes dependent on CALCIUM. A wide range of proteins can act as acceptor, including VIMENTIN; SYNAPSINS; GLYCOGEN SYNTHASE; MYOSIN LIGHT CHAINS; and the MICROTUBULE-ASSOCIATED PROTEINS. (From Enzyme Nomenclature, 1992, p277)Actins: Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.rhoA GTP-Binding Protein: A RHO GTP-BINDING PROTEIN involved in regulating signal transduction pathways that control assembly of focal adhesions and actin stress fibers. This enzyme was formerly listed as EC 18.104.22.168.Recombinant Fusion Proteins: Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.Trans-Activators: Diffusible gene products that act on homologous or heterologous molecules of viral or cellular DNA to regulate the expression of proteins.Mitogen-Activated Protein Kinases: A superfamily of PROTEIN-SERINE-THREONINE KINASES that are activated by diverse stimuli via protein kinase cascades. They are the final components of the cascades, activated by phosphorylation by MITOGEN-ACTIVATED PROTEIN KINASE KINASES, which in turn are activated by mitogen-activated protein kinase kinase kinases (MAP KINASE KINASE KINASES).Cell Nucleus: Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)COS Cells: CELL LINES derived from the CV-1 cell line by transformation with a replication origin defective mutant of SV40 VIRUS, which codes for wild type large T antigen (ANTIGENS, POLYOMAVIRUS TRANSFORMING). They are used for transfection and cloning. (The CV-1 cell line was derived from the kidney of an adult male African green monkey (CERCOPITHECUS AETHIOPS).)Genes, Immediate-Early: Genes that show rapid and transient expression in the absence of de novo protein synthesis. The term was originally used exclusively for viral genes where immediate-early referred to transcription immediately following virus integration into the host cell. It is also used to describe cellular genes which are expressed immediately after resting cells are stimulated by extracellular signals such as growth factors and neurotransmitters.Proto-Oncogene Proteins c-raf: A ubiquitously expressed raf kinase subclass that plays an important role in SIGNAL TRANSDUCTION. The c-raf Kinases are MAP kinase kinase kinases that have specificity for MAP KINASE KINASE 1 and MAP KINASE KINASE 2.DNA Transposable Elements: Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.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.Genes, jun: Retrovirus-associated DNA sequences (jun) originally isolated from the avian sarcoma virus 17 (ASV 17). The proto-oncogene jun (c-jun) codes for a nuclear protein which is involved in growth-related transcriptional control. Insertion of c-jun into ASV-17 or the constitutive expression of the c-jun protein produces tumorgenicity. The human c-jun gene is located at 1p31-32 on the short arm of chromosome 1.Ternary Complex Factors: A subclass of c-ets proto-oncogene proteins that were first described by their property of binding to DNA when associated with other regulatory proteins such as SERUM RESPONSE FACTOR. They contain an amino-terminal ets domain that binds to DNA along with centrally located SERUM RESPONSE FACTOR interacting domain, and carboxy-terminal map kinase activation domains. They play an important role in transcriptional regulation by INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.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.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.Tetradecanoylphorbol Acetate: A phorbol ester found in CROTON OIL with very effective tumor promoting activity. It stimulates the synthesis of both DNA and RNA.Oligonucleotide Probes: Synthetic or natural oligonucleotides used in hybridization studies in order to identify and study specific nucleic acid fragments, e.g., DNA segments near or within a specific gene locus or gene. The probe hybridizes with a specific mRNA, if present. Conventional techniques used for testing for the hybridization product include dot blot assays, Southern blot assays, and DNA:RNA hybrid-specific antibody tests. Conventional labels for the probe include the radioisotope labels 32P and 125I and the chemical label biotin.Repressor Proteins: Proteins which maintain the transcriptional quiescence of specific GENES or OPERONS. Classical repressor proteins are DNA-binding proteins that are normally bound to the OPERATOR REGION of an operon, or the ENHANCER SEQUENCES of a gene until a signal occurs that causes their release.Protein-Tyrosine Kinases: Protein kinases that catalyze the PHOSPHORYLATION of TYROSINE residues in proteins with ATP or other nucleotides as phosphate donors.MAP Kinase Kinase 1: An abundant 43-kDa mitogen-activated protein kinase kinase subtype with specificity for MITOGEN-ACTIVATED PROTEIN KINASE 1 and MITOGEN-ACTIVATED PROTEIN KINASE 3.Proto-Oncogene Proteins c-jun: Cellular DNA-binding proteins encoded by the c-jun genes (GENES, JUN). They are involved in growth-related transcriptional control. There appear to be three distinct functions: dimerization (with c-fos), DNA-binding, and transcriptional activation. Oncogenic transformation can take place by constitutive expression of c-jun.Blood: The body fluid that circulates in the vascular system (BLOOD VESSELS). Whole blood includes PLASMA and BLOOD CELLS.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Receptors, Retinoic Acid: Proteins in the nucleus or cytoplasm that specifically bind RETINOIC ACID or RETINOL and trigger changes in the behavior of cells. Retinoic acid receptors, like steroid receptors, are ligand-activated transcription regulators. Several types have been recognized.GTP Phosphohydrolases: Enzymes that hydrolyze GTP to GDP. EC 3.6.1.-.Mitogen-Activated Protein Kinase 1: A proline-directed serine/threonine protein kinase which mediates signal transduction from the cell surface to the nucleus. Activation of the enzyme by phosphorylation leads to its translocation into the nucleus where it acts upon specific transcription factors. p40 MAPK and p41 MAPK are isoforms.Cyclic AMP Response Element Modulator: Cyclic AMP response element modulator is a basic leucine zipper transcription factor that is regulated by CYCLIC AMP. It plays an important role in SPERMATID development in the mammalian TESTIS.Retinoid X Receptors: A subtype of RETINOIC ACID RECEPTORS that are specific for 9-cis-retinoic acid which function as nuclear TRANSCRIPTION FACTORS that regulate multiple signaling pathways.Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Serum Albumin: A major protein in the BLOOD. It is important in maintaining the colloidal osmotic pressure and transporting large organic molecules.Mitogen-Activated Protein Kinase 3: A 44-kDa extracellular signal-regulated MAP kinase that may play a role the initiation and regulation of MEIOSIS; MITOSIS; and postmitotic functions in differentiated cells. It phosphorylates a number of TRANSCRIPTION FACTORS; and MICROTUBULE-ASSOCIATED PROTEINS.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.Restriction Mapping: Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.Protein-Serine-Threonine Kinases: A group of enzymes that catalyzes the phosphorylation of serine or threonine residues in proteins, with ATP or other nucleotides as phosphate donors.Epidermal Growth Factor: A 6-kDa polypeptide growth factor initially discovered in mouse submaxillary glands. Human epidermal growth factor was originally isolated from urine based on its ability to inhibit gastric secretion and called urogastrone. Epidermal growth factor exerts a wide variety of biological effects including the promotion of proliferation and differentiation of mesenchymal and EPITHELIAL CELLS. It is synthesized as a transmembrane protein which can be cleaved to release a soluble active form.Mitogen-Activated Protein Kinase Kinases: A serine-threonine protein kinase family whose members are components in protein kinase cascades activated by diverse stimuli. These MAPK kinases phosphorylate MITOGEN-ACTIVATED PROTEIN KINASES and are themselves phosphorylated by MAP KINASE KINASE KINASES. JNK kinases (also known as SAPK kinases) are a subfamily.TATA Box: A conserved A-T rich sequence which is contained in promoters for RNA polymerase II. The segment is seven base pairs long and the nucleotides most commonly found are TATAAAA.Vitamin D Response Element: A DNA sequence that is found in the promoter region of vitamin D regulated genes. Vitamin D receptor (RECEPTOR, CALCITRIOL) binds to and regulates the activity of genes containing this element.GTP-Binding Proteins: Regulatory proteins that act as molecular switches. They control a wide range of biological processes including: receptor signaling, intracellular signal transduction pathways, and protein synthesis. Their activity is regulated by factors that control their ability to bind to and hydrolyze GTP to GDP. EC 3.6.1.-.Enzyme Activation: Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.Receptors, Thyroid Hormone: Specific high affinity binding proteins for THYROID HORMONES in target cells. They are usually found in the nucleus and regulate DNA transcription. These receptors are activated by hormones that leads to transcription, cell differentiation, and growth suppression. Thyroid hormone receptors are encoded by two genes (GENES, ERBA): erbA-alpha and erbA-beta for alpha and beta thyroid hormone receptors, respectively.Cyclic AMP: An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.rac GTP-Binding Proteins: A sub-family of RHO GTP-BINDING PROTEINS that is involved in regulating the organization of cytoskeletal filaments. This enzyme was formerly listed as EC 22.214.171.124.Electrophoretic Mobility Shift Assay: An electrophoretic technique for assaying the binding of one compound to another. Typically one compound is labeled to follow its mobility during electrophoresis. If the labeled compound is bound by the other compound, then the mobility of the labeled compound through the electrophoretic medium will be retarded.Sequence Homology, Nucleic Acid: The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.Consensus Sequence: A theoretical representative nucleotide or amino acid sequence in which each nucleotide or amino acid is the one which occurs most frequently at that site in the different sequences which occur in nature. The phrase also refers to an actual sequence which approximates the theoretical consensus. A known CONSERVED SEQUENCE set is represented by a consensus sequence. Commonly observed supersecondary protein structures (AMINO ACID MOTIFS) are often formed by conserved sequences.Mitogens: Substances that stimulate mitosis and lymphocyte transformation. They include not only substances associated with LECTINS, but also substances from streptococci (associated with streptolysin S) and from strains of alpha-toxin-producing staphylococci. (Stedman, 25th ed)Myocardium: The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.ras Proteins: Small, monomeric GTP-binding proteins encoded by ras genes (GENES, RAS). The protooncogene-derived protein, PROTO-ONCOGENE PROTEIN P21(RAS), plays a role in normal cellular growth, differentiation and development. The oncogene-derived protein (ONCOGENE PROTEIN P21(RAS)) can play a role in aberrant cellular regulation during neoplastic cell transformation (CELL TRANSFORMATION, NEOPLASTIC). This enzyme was formerly listed as EC 126.96.36.199.Antioxidant Response Elements: Nucleotide sequences that are found in the PROMOTER REGIONS of the genes of stress-responsive and cytoprotective proteins, such as those encoding antioxidant and PHASE II DETOXIFICATION enzymes. NF-E2-RELATED FACTOR 2 containing transcription factors bind to these elements during induction of these genes.Atrial Natriuretic Factor: A potent natriuretic and vasodilatory peptide or mixture of different-sized low molecular weight PEPTIDES derived from a common precursor and secreted mainly by the HEART ATRIUM. All these peptides share a sequence of about 20 AMINO ACIDS.MAP Kinase Signaling System: An intracellular signaling system involving the MAP kinase cascades (three-membered protein kinase cascades). Various upstream activators, which act in response to extracellular stimuli, trigger the cascades by activating the first member of a cascade, MAP KINASE KINASE KINASES; (MAPKKKs). Activated MAPKKKs phosphorylate MITOGEN-ACTIVATED PROTEIN KINASE KINASES which in turn phosphorylate the MITOGEN-ACTIVATED PROTEIN KINASES; (MAPKs). The MAPKs then act on various downstream targets to affect gene expression. In mammals, there are several distinct MAP kinase pathways including the ERK (extracellular signal-regulated kinase) pathway, the SAPK/JNK (stress-activated protein kinase/c-jun kinase) pathway, and the p38 kinase pathway. There is some sharing of components among the pathways depending on which stimulus originates activation of the cascade.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.Genes, ras: Family of retrovirus-associated DNA sequences (ras) originally isolated from Harvey (H-ras, Ha-ras, rasH) and Kirsten (K-ras, Ki-ras, rasK) murine sarcoma viruses. Ras genes are widely conserved among animal species and sequences corresponding to both H-ras and K-ras genes have been detected in human, avian, murine, and non-vertebrate genomes. The closely related N-ras gene has been detected in human neuroblastoma and sarcoma cell lines. All genes of the family have a similar exon-intron structure and each encodes a p21 protein.CREB-Binding Protein: A member of the p300-CBP transcription factor family that was initially identified as a binding partner for CAMP RESPONSE ELEMENT-BINDING PROTEIN. Mutations in CREB-binding protein are associated with RUBINSTEIN-TAYBI SYNDROME.Transcription Factor AP-1: A multiprotein complex composed of the products of c-jun and c-fos proto-oncogenes. These proteins must dimerize in order to bind to the AP-1 recognition site, also known as the TPA-responsive element (TRE). AP-1 controls both basal and inducible transcription of several genes.Enzyme Inhibitors: Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.Receptors, Cytoplasmic and Nuclear: Intracellular receptors that can be found in the cytoplasm or in the nucleus. They bind to extracellular signaling molecules that migrate through or are transported across the CELL MEMBRANE. Many members of this class of receptors occur in the cytoplasm and are transported to the CELL NUCLEUS upon ligand-binding where they signal via DNA-binding and transcription regulation. Also included in this category are receptors found on INTRACELLULAR MEMBRANES that act via mechanisms similar to CELL SURFACE RECEPTORS.Protein Kinase C: An serine-threonine protein kinase that requires the presence of physiological concentrations of CALCIUM and membrane PHOSPHOLIPIDS. The additional presence of DIACYLGLYCEROLS markedly increases its sensitivity to both calcium and phospholipids. The sensitivity of the enzyme can also be increased by PHORBOL ESTERS and it is believed that protein kinase C is the receptor protein of tumor-promoting phorbol esters.Sequence Deletion: Deletion of sequences of nucleic acids from the genetic material of an individual.NF-E2-Related Factor 2: A basic-leucine zipper transcription factor that was originally described as a transcriptional regulator controlling expression of the BETA-GLOBIN gene. It may regulate the expression of a wide variety of genes that play a role in protecting cells from oxidative damage.Repetitive Sequences, Nucleic Acid: Sequences of DNA or RNA that occur in multiple copies. There are several types: INTERSPERSED REPETITIVE SEQUENCES are copies of transposable elements (DNA TRANSPOSABLE ELEMENTS or RETROELEMENTS) dispersed throughout the genome. TERMINAL REPEAT SEQUENCES flank both ends of another sequence, for example, the long terminal repeats (LTRs) on RETROVIRUSES. Variations may be direct repeats, those occurring in the same direction, or inverted repeats, those opposite to each other in direction. TANDEM REPEAT SEQUENCES are copies which lie adjacent to each other, direct or inverted (INVERTED REPEAT SEQUENCES).Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.Receptors, Glucocorticoid: Cytoplasmic proteins that specifically bind glucocorticoids and mediate their cellular effects. The glucocorticoid receptor-glucocorticoid complex acts in the nucleus to induce transcription of DNA. Glucocorticoids were named for their actions on blood glucose concentration, but they have equally important effects on protein and fat metabolism. Cortisol is the most important example.Chromatin Immunoprecipitation: A technique for identifying specific DNA sequences that are bound, in vivo, to proteins of interest. It involves formaldehyde fixation of CHROMATIN to crosslink the DNA-BINDING PROTEINS to the DNA. After shearing the DNA into small fragments, specific DNA-protein complexes are isolated by immunoprecipitation with protein-specific ANTIBODIES. Then, the DNA isolated from the complex can be identified by PCR amplification and sequencing.Trace Elements: A group of chemical elements that are needed in minute quantities for the proper growth, development, and physiology of an organism. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Time Factors: Elements of limited time intervals, contributing to particular results or situations.YY1 Transcription Factor: A ubiquitously expressed zinc finger-containing protein that acts both as a repressor and activator of transcription. It interacts with key regulatory proteins such as TATA-BINDING PROTEIN; TFIIB; and ADENOVIRUS E1A PROTEINS.Sp1 Transcription Factor: Promoter-specific RNA polymerase II transcription factor that binds to the GC box, one of the upstream promoter elements, in mammalian cells. The binding of Sp1 is necessary for the initiation of transcription in the promoters of a variety of cellular and viral GENES.Conserved Sequence: A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.DNA Footprinting: A method for determining the sequence specificity of DNA-binding proteins. DNA footprinting utilizes a DNA damaging agent (either a chemical reagent or a nuclease) which cleaves DNA at every base pair. DNA cleavage is inhibited where the ligand binds to DNA. (from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.Finite Element Analysis: A computer based method of simulating or analyzing the behavior of structures or components.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.Introns: Sequences of DNA in the genes that are located between the EXONS. They are transcribed along with the exons but are removed from the primary gene transcript by RNA SPLICING to leave mature RNA. Some introns code for separate genes.Homeodomain Proteins: Proteins encoded by homeobox genes (GENES, HOMEOBOX) that exhibit structural similarity to certain prokaryotic and eukaryotic DNA-binding proteins. Homeodomain proteins are involved in the control of gene expression during morphogenesis and development (GENE EXPRESSION REGULATION, DEVELOPMENTAL).Elements: Substances that comprise all matter. Each element is made up of atoms that are identical in number of electrons and protons and in nuclear charge, but may differ in mass or number of neutrons.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.Receptors, Steroid: Proteins found usually in the cytoplasm or nucleus that specifically bind steroid hormones and trigger changes influencing the behavior of cells. The steroid receptor-steroid hormone complex regulates the transcription of specific genes.CCAAT-Enhancer-Binding Proteins: A class of proteins that were originally identified by their ability to bind the DNA sequence CCAAT. The typical CCAAT-enhancer binding protein forms dimers and consists of an activation domain, a DNA-binding basic region, and a leucine-rich dimerization domain (LEUCINE ZIPPERS). CCAAT-BINDING FACTOR is structurally distinct type of CCAAT-enhancer binding protein consisting of a trimer of three different subunits.Mice, Transgenic: Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.Tretinoin: An important regulator of GENE EXPRESSION during growth and development, and in NEOPLASMS. Tretinoin, also known as retinoic acid and derived from maternal VITAMIN A, is essential for normal GROWTH; and EMBRYONIC DEVELOPMENT. An excess of tretinoin can be teratogenic. It is used in the treatment of PSORIASIS; ACNE VULGARIS; and several other SKIN DISEASES. It has also been approved for use in promyelocytic leukemia (LEUKEMIA, PROMYELOCYTIC, ACUTE).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.Regulatory Elements, Transcriptional: Nucleotide sequences of a gene that are involved in the regulation of GENETIC TRANSCRIPTION.Cell Line, Tumor: A cell line derived from cultured tumor cells.NIH 3T3 Cells: A continuous cell line of high contact-inhibition established from NIH Swiss mouse embryo cultures. The cells are useful for DNA transfection and transformation studies. (From ATCC [Internet]. Virginia: American Type Culture Collection; c2002 [cited 2002 Sept 26]. Available from http://www.atcc.org/)Triiodothyronine: A T3 thyroid hormone normally synthesized and secreted by the thyroid gland in much smaller quantities than thyroxine (T4). Most T3 is derived from peripheral monodeiodination of T4 at the 5' position of the outer ring of the iodothyronine nucleus. The hormone finally delivered and used by the tissues is mainly T3.Microfilament Proteins: Monomeric subunits of primarily globular ACTIN and found in the cytoplasmic matrix of almost all cells. They are often associated with microtubules and may play a role in cytoskeletal function and/or mediate movement of the cell or the organelles within the cell.Alu Elements: The Alu sequence family (named for the restriction endonuclease cleavage enzyme Alu I) is the most highly repeated interspersed repeat element in humans (over a million copies). It is derived from the 7SL RNA component of the SIGNAL RECOGNITION PARTICLE and contains an RNA polymerase III promoter. Transposition of this element into coding and regulatory regions of genes is responsible for many heritable diseases.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.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Serum Albumin, Bovine: Serum albumin from cows, commonly used in in vitro biological studies. (From Stedman, 25th ed)Oligonucleotides: Polymers made up of a few (2-20) nucleotides. In molecular genetics, they refer to a short sequence synthesized to match a region where a mutation is known to occur, and then used as a probe (OLIGONUCLEOTIDE PROBES). (Dorland, 28th ed)Cercopithecus aethiops: A species of CERCOPITHECUS containing three subspecies: C. tantalus, C. pygerythrus, and C. sabeus. They are found in the forests and savannah of Africa. The African green monkey (C. pygerythrus) is the natural host of SIMIAN IMMUNODEFICIENCY VIRUS and is used in AIDS research.Myocytes, Smooth Muscle: Non-striated, elongated, spindle-shaped cells found lining the digestive tract, uterus, and blood vessels. They are derived from specialized myoblasts (MYOBLASTS, SMOOTH MUSCLE).Up-Regulation: A positive regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.Dimerization: The process by which two molecules of the same chemical composition form a condensation product or polymer.Gene Expression Regulation, Developmental: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Nucleic Acid Conformation: The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.Organ Specificity: Characteristic restricted to a particular organ of the body, such as a cell type, metabolic response or expression of a particular protein or antigen.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.Models, Genetic: Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Deoxyribonuclease I: An enzyme capable of hydrolyzing highly polymerized DNA by splitting phosphodiester linkages, preferentially adjacent to a pyrimidine nucleotide. This catalyzes endonucleolytic cleavage of DNA yielding 5'-phosphodi- and oligonucleotide end-products. The enzyme has a preference for double-stranded DNA.Muscle Proteins: The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.5' Flanking Region: The region of DNA which borders the 5' end of a transcription unit and where a variety of regulatory sequences are located.Zinc Fingers: Motifs in DNA- and RNA-binding proteins whose amino acids are folded into a single structural unit around a zinc atom. In the classic zinc finger, one zinc atom is bound to two cysteines and two histidines. In between the cysteines and histidines are 12 residues which form a DNA binding fingertip. By variations in the composition of the sequences in the fingertip and the number and spacing of tandem repeats of the motif, zinc fingers can form a large number of different sequence specific binding sites.Mice, Inbred C57BLCarrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.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.Mutagenesis: Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.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.DNA Mutational Analysis: Biochemical identification of mutational changes in a nucleotide sequence.Down-Regulation: A negative regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.Long Interspersed Nucleotide Elements: Highly repeated sequences, 6K-8K base pairs in length, which contain RNA polymerase II promoters. They also have an open reading frame that is related to the reverse transcriptase of retroviruses but they do not contain LTRs (long terminal repeats). Copies of the LINE 1 (L1) family form about 15% of the human genome. The jockey elements of Drosophila are LINEs.Genes, Regulator: Genes which regulate or circumscribe the activity of other genes; specifically, genes which code for PROTEINS or RNAs which have GENE EXPRESSION REGULATION functions.Glucocorticoids: A group of CORTICOSTEROIDS that affect carbohydrate metabolism (GLUCONEOGENESIS, liver glycogen deposition, elevation of BLOOD SUGAR), inhibit ADRENOCORTICOTROPIC HORMONE secretion, and possess pronounced anti-inflammatory activity. They also play a role in fat and protein metabolism, maintenance of arterial blood pressure, alteration of the connective tissue response to injury, reduction in the number of circulating lymphocytes, and functioning of the central nervous system.GTP-Binding Protein alpha Subunits, G12-G13: A ubiquitously expressed family of heterotrimeric GTP-binding protein alpha subunits that signal through interactions with a variety of second messengers as GTPASE-ACTIVATING PROTEINS; GUANINE NUCLEOTIDE EXCHANGE FACTORS; and HEAT SHOCK PROTEINS. The G12-G13 part of the name is also spelled G12/G13.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Receptors, Calcitriol: Proteins, usually found in the cytoplasm, that specifically bind calcitriol, migrate to the nucleus, and regulate transcription of specific segments of DNA with the participation of D receptor interacting proteins (called DRIP). Vitamin D is converted in the liver and kidney to calcitriol and ultimately acts through these receptors.Glutathione Transferase: A transferase that catalyzes the addition of aliphatic, aromatic, or heterocyclic FREE RADICALS as well as EPOXIDES and arene oxides to GLUTATHIONE. Addition takes place at the SULFUR. It also catalyzes the reduction of polyol nitrate by glutathione to polyol and nitrite.beta-Galactosidase: A group of enzymes that catalyzes the hydrolysis of terminal, non-reducing beta-D-galactose residues in beta-galactosides. Deficiency of beta-Galactosidase A1 may cause GANGLIOSIDOSIS, GM1.Erythroid-Specific DNA-Binding Factors: A group of transcription factors that were originally described as being specific to ERYTHROID CELLS.Cyclic AMP-Dependent Protein Kinases: A group of enzymes that are dependent on CYCLIC AMP and catalyze the phosphorylation of SERINE or THREONINE residues on proteins. Included under this category are two cyclic-AMP-dependent protein kinase subtypes, each of which is defined by its subunit composition.Thyroid Hormones: Natural hormones secreted by the THYROID GLAND, such as THYROXINE, and their synthetic analogs.RNA, Small Interfering: Small double-stranded, non-protein coding RNAs (21-31 nucleotides) involved in GENE SILENCING functions, especially RNA INTERFERENCE (RNAi). Endogenously, siRNAs are generated from dsRNAs (RNA, DOUBLE-STRANDED) by the same ribonuclease, Dicer, that generates miRNAs (MICRORNAS). The perfect match of the siRNAs' antisense strand to their target RNAs mediates RNAi by siRNA-guided RNA cleavage. siRNAs fall into different classes including trans-acting siRNA (tasiRNA), repeat-associated RNA (rasiRNA), small-scan RNA (scnRNA), and Piwi protein-interacting RNA (piRNA) and have different specific gene silencing functions.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.Estrogens: Compounds that interact with ESTROGEN RECEPTORS in target tissues to bring about the effects similar to those of ESTRADIOL. Estrogens stimulate the female reproductive organs, and the development of secondary female SEX CHARACTERISTICS. Estrogenic chemicals include natural, synthetic, steroidal, or non-steroidal compounds.NF-kappa B: Ubiquitous, inducible, nuclear transcriptional activator that binds to enhancer elements in many different cell types and is activated by pathogenic stimuli. The NF-kappa B complex is a heterodimer composed of two DNA-binding subunits: NF-kappa B1 and relA.Dexamethasone: An anti-inflammatory 9-fluoro-glucocorticoid.Chickens: Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.Activating Transcription Factor 2: An activating transcription factor that regulates expression of a variety of GENES including C-JUN GENES; CYCLIN A; CYCLIN D1; and ACTIVATING TRANSCRIPTION FACTOR 3.Short Interspersed Nucleotide Elements: Highly repeated sequences, 100-300 bases long, which contain RNA polymerase III promoters. The primate Alu (ALU ELEMENTS) and the rodent B1 SINEs are derived from 7SL RNA, the RNA component of the signal recognition particle. Most other SINEs are derived from tRNAs including the MIRs (mammalian-wide interspersed repeats).Two-Hybrid System Techniques: Screening techniques first developed in yeast to identify genes encoding interacting proteins. Variations are used to evaluate interplay between proteins and other molecules. Two-hybrid techniques refer to analysis for protein-protein interactions, one-hybrid for DNA-protein interactions, three-hybrid interactions for RNA-protein interactions or ligand-based interactions. Reverse n-hybrid techniques refer to analysis for mutations or other small molecules that dissociate known interactions.Genes: A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.Activating Transcription Factor 1: An activating transcription factor that regulates expression of a variety of genes including C-JUN GENES and TRANSFORMING GROWTH FACTOR BETA2.Muscle, Smooth: Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)Receptors, Estrogen: Cytoplasmic proteins that bind estrogens and migrate to the nucleus where they regulate DNA transcription. Evaluation of the state of estrogen receptors in breast cancer patients has become clinically important.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.Integrin alpha1: An integrin alpha subunit that binds COLLAGEN and LAMININ though its I domain. It combines with INTEGRIN BETA1 to form the heterodimer INTEGRIN ALPHA1BETA1.Protein Isoforms: Different forms of a protein that may be produced from different GENES, or from the same gene by ALTERNATIVE SPLICING.Binding, Competitive: The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.Embryo, Mammalian: The entity of a developing mammal (MAMMALS), generally from the cleavage of a ZYGOTE to the end of embryonic differentiation of basic structures. For the human embryo, this represents the first two months of intrauterine development preceding the stages of the FETUS.Gene Expression Regulation, Neoplastic: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in neoplastic tissue.Activating Transcription Factor 6: One of the BASIC-LEUCINE ZIPPER TRANSCRIPTION FACTORS that is synthesized as a membrane-bound protein in the ENDOPLASMIC RETICULUM. In response to endoplasmic reticulum stress it translocates to the GOLGI APPARATUS. It is activated by PROTEASES and then moves to the CELL NUCLEUS to regulate GENETIC TRANSCRIPTION of GENES involved in the unfolded protein response.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)Estradiol: The 17-beta-isomer of estradiol, an aromatized C18 steroid with hydroxyl group at 3-beta- and 17-beta-position. Estradiol-17-beta is the most potent form of mammalian estrogenic steroids.Leucine Zippers: DNA-binding motifs formed from two alpha-helixes which intertwine for about eight turns into a coiled coil and then bifurcate to form Y shaped structures. Leucines occurring in heptad repeats end up on the same sides of the helixes and are adjacent to each other in the stem of the Y (the "zipper" region). The DNA-binding residues are located in the bifurcated region of the Y.Biological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Gene Expression Regulation, Viral: Any of the processes by which cytoplasmic factors influence the differential control of gene action in viruses.Muscle, Smooth, Vascular: The nonstriated involuntary muscle tissue of blood vessels.