Mice, Transgenic: Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.Mice, Inbred C57BLTransgenes: Genes that are introduced into an organism using GENE TRANSFER TECHNIQUES.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Plants, Genetically Modified: PLANTS, or their progeny, whose GENOME has been altered by GENETIC ENGINEERING.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Rats, Transgenic: Laboratory rats that have been produced from a genetically manipulated rat EGG or rat EMBRYO, MAMMALIAN. They contain genes from another species.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.Animals, Genetically Modified: ANIMALS whose GENOME has been altered by GENETIC ENGINEERING, or their offspring.Crosses, Genetic: Deliberate breeding of two different individuals that results in offspring that carry part of the genetic material of each parent. The parent organisms must be genetically compatible and may be from different varieties or closely related species.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.Thymus Gland: A single, unpaired primary lymphoid organ situated in the MEDIASTINUM, extending superiorly into the neck to the lower edge of the THYROID GLAND and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.Mice, Inbred CBAReceptors, Antigen, T-Cell, alpha-beta: T-cell receptors composed of CD3-associated alpha and beta polypeptide chains and expressed primarily in CD4+ or CD8+ T-cells. Unlike immunoglobulins, the alpha-beta T-cell receptors recognize antigens only when presented in association with major histocompatibility (MHC) molecules.H-2 Antigens: The major group of transplantation antigens in the mouse.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.T-Lymphocytes: Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Clonal Deletion: Removal, via CELL DEATH, of immature lymphocytes that interact with antigens during maturation. For T-lymphocytes this occurs in the thymus and ensures that mature T-lymphocytes are self tolerant. B-lymphocytes may also undergo clonal deletion.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.B-Lymphocytes: Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.Spleen: An encapsulated lymphatic organ through which venous blood filters.Mice, Inbred DBAReceptors, Antigen, T-Cell: Molecules on the surface of T-lymphocytes that recognize and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens (ANTIGENS, CD3). Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta (RECEPTORS, ANTIGEN, T-CELL, ALPHA-BETA) or gamma-delta (RECEPTORS, ANTIGEN, T-CELL, GAMMA-DELTA) chains.Epitopes, T-Lymphocyte: Antigenic determinants recognized and bound by the T-cell receptor. Epitopes recognized by the T-cell receptor are often located in the inner, unexposed side of the antigen, and become accessible to the T-cell receptors after proteolytic processing of the antigen.Immune Tolerance: The specific failure of a normally responsive individual to make an immune response to a known antigen. It results from previous contact with the antigen by an immunologically immature individual (fetus or neonate) or by an adult exposed to extreme high-dose or low-dose antigen, or by exposure to radiation, antimetabolites, antilymphocytic serum, etc.Antigens, Polyomavirus Transforming: Polyomavirus antigens which cause infection and cellular transformation. The large T antigen is necessary for the initiation of viral DNA synthesis, repression of transcription of the early region and is responsible in conjunction with the middle T antigen for the transformation of primary cells. Small T antigen is necessary for the completion of the productive infection cycle.Green Fluorescent Proteins: Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.CD4-Positive T-Lymphocytes: A critical subpopulation of T-lymphocytes involved in the induction of most immunological functions. The HIV virus has selective tropism for the T4 cell which expresses the CD4 phenotypic marker, a receptor for HIV. In fact, the key element in the profound immunosuppression seen in HIV infection is the depletion of this subset of T-lymphocytes.Lymphocyte Activation: Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.Mice, Inbred BALB CPhenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Papillomavirus E7 Proteins: ONCOGENE PROTEINS from papillomavirus that deregulate the CELL CYCLE of infected cells and lead to NEOPLASTIC CELL TRANSFORMATION. Papillomavirus E7 proteins have been shown to interact with various regulators of the cell cycle including RETINOBLASTOMA PROTEIN and certain cyclin-dependent kinase inhibitors.Immunization: Deliberate stimulation of the host's immune response. ACTIVE IMMUNIZATION involves administration of ANTIGENS or IMMUNOLOGIC ADJUVANTS. PASSIVE IMMUNIZATION involves administration of IMMUNE SERA or LYMPHOCYTES or their extracts (e.g., transfer factor, immune RNA) or transplantation of immunocompetent cell producing tissue (thymus or bone marrow).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.Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.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.Hybridomas: Cells artificially created by fusion of activated lymphocytes with neoplastic cells. The resulting hybrid cells are cloned and produce pure MONOCLONAL ANTIBODIES or T-cell products, identical to those produced by the immunologically competent parent cell.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.Immunoglobulin kappa-Chains: One of the types of light chains of the immunoglobulins with a molecular weight of approximately 22 kDa.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Flow Cytometry: Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.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.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.Autoantigens: Endogenous tissue constituents that have the ability to interact with AUTOANTIBODIES and cause an immune response.Cancer Vaccines: Vaccines or candidate vaccines designed to prevent or treat cancer. Vaccines are produced using the patient's own whole tumor cells as the source of antigens, or using tumor-specific antigens, often recombinantly produced.T-Lymphocytes, Cytotoxic: Immunized T-lymphocytes which can directly destroy appropriate target cells. These cytotoxic lymphocytes may be generated in vitro in mixed lymphocyte cultures (MLC), in vivo during a graft-versus-host (GVH) reaction, or after immunization with an allograft, tumor cell or virally transformed or chemically modified target cell. The lytic phenomenon is sometimes referred to as cell-mediated lympholysis (CML). These CD8-positive cells are distinct from NATURAL KILLER CELLS and NATURAL KILLER T-CELLS. There are two effector phenotypes: TC1 and TC2.T-Lymphocyte Subsets: A classification of T-lymphocytes, especially into helper/inducer, suppressor/effector, and cytotoxic subsets, based on structurally or functionally different populations of cells.Antigens, CD4: 55-kDa antigens found on HELPER-INDUCER T-LYMPHOCYTES and on a variety of other immune cell types. CD4 antigens are members of the immunoglobulin supergene family and are implicated as associative recognition elements in MAJOR HISTOCOMPATIBILITY COMPLEX class II-restricted immune responses. On T-lymphocytes they define the helper/inducer subset. CD4 antigens also serve as INTERLEUKIN-15 receptors and bind to the HIV receptors, binding directly to the HIV ENVELOPE PROTEIN GP120.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.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Cell Division: The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.Immunoglobulin G: The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Membrane Glycoproteins: Glycoproteins found on the membrane or surface of cells.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Autoantibodies: Antibodies that react with self-antigens (AUTOANTIGENS) of the organism that produced them.Antigens, CD: Differentiation antigens residing on mammalian leukocytes. CD stands for cluster of differentiation, which refers to groups of monoclonal antibodies that show similar reactivity with certain subpopulations of antigens of a particular lineage or differentiation stage. The subpopulations of antigens are also known by the same CD designation.Tobacco: A plant genus of the family SOLANACEAE. Members contain NICOTINE and other biologically active chemicals; its dried leaves are used for SMOKING.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.CD8-Positive T-Lymphocytes: A critical subpopulation of regulatory T-lymphocytes involved in MHC Class I-restricted interactions. They include both cytotoxic T-lymphocytes (T-LYMPHOCYTES, CYTOTOXIC) and CD8+ suppressor T-lymphocytes.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.Interferon-gamma: The major interferon produced by mitogenically or antigenically stimulated LYMPHOCYTES. It is structurally different from TYPE I INTERFERON and its major activity is immunoregulation. It has been implicated in the expression of CLASS II HISTOCOMPATIBILITY ANTIGENS in cells that do not normally produce them, leading to AUTOIMMUNE DISEASES.Cytotoxicity, Immunologic: The phenomenon of target cell destruction by immunologically active effector cells. It may be brought about directly by sensitized T-lymphocytes or by lymphoid or myeloid "killer" cells, or it may be mediated by cytotoxic antibody, cytotoxic factor released by lymphoid cells, or complement.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.Cytokines: Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner.Interleukin-4: A soluble factor produced by activated T-LYMPHOCYTES that induces the expression of MHC CLASS II GENES and FC RECEPTORS on B-LYMPHOCYTES and causes their proliferation and differentiation. It also acts on T-lymphocytes, MAST CELLS, and several other hematopoietic lineage cells.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.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Plants, Toxic: Plants or plant parts which are harmful to man or other animals.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.Gene Expression Regulation, Plant: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.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.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.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.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.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.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.Amyloid beta-Protein Precursor: A single-pass type I membrane protein. It is cleaved by AMYLOID PRECURSOR PROTEIN SECRETASES to produce peptides of varying amino acid lengths. A 39-42 amino acid peptide, AMYLOID BETA-PEPTIDES is a principal component of the extracellular amyloid in SENILE PLAQUES.Luminescent Proteins: Proteins which are involved in the phenomenon of light emission in living systems. Included are the "enzymatic" and "non-enzymatic" types of system with or without the presence of oxygen or co-factors.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)Transformation, Genetic: Change brought about to an organisms genetic composition by unidirectional transfer (TRANSFECTION; TRANSDUCTION, GENETIC; CONJUGATION, GENETIC, etc.) and incorporation of foreign DNA into prokaryotic or eukaryotic cells by recombination of part or all of that DNA into the cell's genome.Integrases: Recombinases that insert exogenous DNA into the host genome. Examples include proteins encoded by the POL GENE of RETROVIRIDAE and also by temperate BACTERIOPHAGES, the best known being BACTERIOPHAGE LAMBDA.Genetic Engineering: Directed modification of the gene complement of a living organism by such techniques as altering the DNA, substituting genetic material by means of a virus, transplanting whole nuclei, transplanting cell hybrids, etc.Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.Alzheimer Disease: A degenerative disease of the BRAIN characterized by the insidious onset of DEMENTIA. Impairment of MEMORY, judgment, attention span, and problem solving skills are followed by severe APRAXIAS and a global loss of cognitive abilities. The condition primarily occurs after age 60, and is marked pathologically by severe cortical atrophy and the triad of SENILE PLAQUES; NEUROFIBRILLARY TANGLES; and NEUROPIL THREADS. (From Adams et al., Principles of Neurology, 6th ed, pp1049-57)Lac Operon: The genetic unit consisting of three structural genes, an operator and a regulatory gene. The regulatory gene controls the synthesis of the three structural genes: BETA-GALACTOSIDASE and beta-galactoside permease (involved with the metabolism of lactose), and beta-thiogalactoside acetyltransferase.Plaque, Amyloid: Accumulations of extracellularly deposited AMYLOID FIBRILS within tissues.Amyloid beta-Peptides: Peptides generated from AMYLOID BETA-PEPTIDES PRECURSOR. An amyloid fibrillar form of these peptides is the major component of amyloid plaques found in individuals with Alzheimer's disease and in aged individuals with trisomy 21 (DOWN SYNDROME). The peptide is found predominantly in the nervous system, but there have been reports of its presence in non-neural tissue.Oryza sativa: Annual cereal grass of the family POACEAE and its edible starchy grain, rice, which is the staple food of roughly one-half of the world's population.Genetic Vectors: DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.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.Zebrafish: An exotic species of the family CYPRINIDAE, originally from Asia, that has been introduced in North America. They are used in embryological studies and to study the effects of certain chemicals on development.Genes, Plant: The functional hereditary units of PLANTS.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.Blotting, Southern: A method (first developed by E.M. Southern) for detection of DNA 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.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.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.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.Gene Transfer Techniques: The introduction of functional (usually cloned) GENES into cells. A variety of techniques and naturally occurring processes are used for the gene transfer such as cell hybridization, LIPOSOMES or microcell-mediated gene transfer, ELECTROPORATION, chromosome-mediated gene transfer, TRANSFECTION, and GENETIC TRANSDUCTION. Gene transfer may result in genetically transformed cells and individual organisms.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.In Situ Hybridization: A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.Plant Diseases: Diseases of plants.Apoptosis: One of the mechanisms by which CELL DEATH occurs (compare with NECROSIS and AUTOPHAGOCYTOSIS). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA; (DNA FRAGMENTATION); at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.Mammary Neoplasms, Experimental: Experimentally induced mammary neoplasms in animals to provide a model for studying human BREAST NEOPLASMS.Doxycycline: A synthetic tetracycline derivative with similar antimicrobial activity.Mice, Inbred Strains: Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations, or by parent x offspring matings carried out with certain restrictions. All animals within an inbred strain trace back to a common ancestor in the twentieth generation.Solanum tuberosum: A plant species of the genus SOLANUM, family SOLANACEAE. The starchy roots are used as food. SOLANINE is found in green parts.Mammary Glands, Animal: MAMMARY GLANDS in the non-human MAMMALS.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.Hyperplasia: An increase in the number of cells in a tissue or organ without tumor formation. It differs from HYPERTROPHY, which is an increase in bulk without an increase in the number of cells.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.Chromosomes, Artificial, Bacterial: DNA constructs that are composed of, at least, a REPLICATION ORIGIN, for successful replication, propagation to and maintenance as an extra chromosome in bacteria. In addition, they can carry large amounts (about 200 kilobases) of other sequence for a variety of bioengineering purposes.Nerve Tissue ProteinsGlucuronidaseCloning, 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.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.Tissue Distribution: Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.Keratin-14: A type I keratin that is found associated with the KERATIN-5 in the internal stratified EPITHELIUM. Mutations in the gene for keratin-14 are associated with EPIDERMOLYSIS BULLOSA SIMPLEX.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.Models, Animal: Non-human animals, selected because of specific characteristics, for use in experimental research, teaching, or testing.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Recombinant Proteins: Proteins prepared by recombinant DNA technology.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.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).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.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)Agrobacterium: A genus of gram negative, aerobic, rod-shaped bacteria found in soil, plants, and marine mud.Aging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.Regulatory Sequences, Nucleic Acid: Nucleic acid sequences involved in regulating the expression of genes.Gene Targeting: The integration of exogenous DNA into the genome of an organism at sites where its expression can be suitably controlled. This integration occurs as a result of homologous recombination.Organisms, Genetically Modified: Organisms whose GENOME has been changed by a GENETIC ENGINEERING technique.Mammary Tumor Virus, Mouse: The type species of BETARETROVIRUS commonly latent in mice. It causes mammary adenocarcinoma in a genetically susceptible strain of mice when the appropriate hormonal influences operate.Presenilin-1: Integral membrane protein of Golgi and endoplasmic reticulum. Its homodimer is an essential component of the gamma-secretase complex that catalyzes the cleavage of membrane proteins such as NOTCH RECEPTORS and AMYLOID BETA-PEPTIDES precursors. PSEN1 mutations cause early-onset ALZHEIMER DISEASE type 3 that may occur as early as 30 years of age in humans.Lycopersicon esculentum: A plant species of the family SOLANACEAE, native of South America, widely cultivated for their edible, fleshy, usually red fruit.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).Animals, Newborn: Refers to animals in the period of time just after birth.tau Proteins: Microtubule-associated proteins that are mainly expressed in neurons. Tau proteins constitute several isoforms and play an important role in the assembly of tubulin monomers into microtubules and in maintaining the cytoskeleton and axonal transport. Aggregation of specific sets of tau proteins in filamentous inclusions is the common feature of intraneuronal and glial fibrillar lesions (NEUROFIBRILLARY TANGLES; NEUROPIL THREADS) in numerous neurodegenerative disorders (ALZHEIMER DISEASE; TAUOPATHIES).Metallothionein: A low-molecular-weight (approx. 10 kD) protein occurring in the cytoplasm of kidney cortex and liver. It is rich in cysteinyl residues and contains no aromatic amino acids. Metallothionein shows high affinity for bivalent heavy metals.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.Huntington Disease: A familial disorder inherited as an autosomal dominant trait and characterized by the onset of progressive CHOREA and DEMENTIA in the fourth or fifth decade of life. Common initial manifestations include paranoia; poor impulse control; DEPRESSION; HALLUCINATIONS; and DELUSIONS. Eventually intellectual impairment; loss of fine motor control; ATHETOSIS; and diffuse chorea involving axial and limb musculature develops, leading to a vegetative state within 10-15 years of disease onset. The juvenile variant has a more fulminant course including SEIZURES; ATAXIA; dementia; and chorea. (From Adams et al., Principles of Neurology, 6th ed, pp1060-4)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.Mice, Inbred C3HCell Proliferation: All of the processes involved in increasing CELL NUMBER including CELL DIVISION.Epidermis: The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of EPITHELIUM: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis).Superoxide Dismutase: An oxidoreductase that catalyzes the reaction between superoxide anions and hydrogen to yield molecular oxygen and hydrogen peroxide. The enzyme protects the cell against dangerous levels of superoxide. EC 1.15.1.1.Trans-Activators: Diffusible gene products that act on homologous or heterologous molecules of viral or cellular DNA to regulate the expression of proteins.Skin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.Cardiomegaly: Enlargement of the HEART, usually indicated by a cardiothoracic ratio above 0.50. Heart enlargement may involve the right, the left, or both HEART VENTRICLES or HEART ATRIA. Cardiomegaly is a nonspecific symptom seen in patients with chronic systolic heart failure (HEART FAILURE) or several forms of CARDIOMYOPATHIES.Keratins: A class of fibrous proteins or scleroproteins that represents the principal constituent of EPIDERMIS; HAIR; NAILS; horny tissues, and the organic matrix of tooth ENAMEL. Two major conformational groups have been characterized, alpha-keratin, whose peptide backbone forms a coiled-coil alpha helical structure consisting of TYPE I KERATIN and a TYPE II KERATIN, and beta-keratin, whose backbone forms a zigzag or pleated sheet structure. alpha-Keratins have been classified into at least 20 subtypes. In addition multiple isoforms of subtypes have been found which may be due to GENE DUPLICATION.Caulimovirus: A genus of PLANT VIRUSES, in the family CAULIMOVIRIDAE, that are transmitted by APHIDS in a semipersistent manner. Aphid-borne transmission of some caulimoviruses requires certain virus-coded proteins termed transmission factors.Cell Transformation, Neoplastic: Cell changes manifested by escape from control mechanisms, increased growth potential, alterations in the cell surface, karyotypic abnormalities, morphological and biochemical deviations from the norm, and other attributes conferring the ability to invade, metastasize, and kill.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.DNA, Plant: Deoxyribonucleic acid that makes up the genetic material of plants.Chimera: An individual that contains cell populations derived from different zygotes.Droughts: Prolonged dry periods in natural climate cycle. They are slow-onset phenomena caused by rainfall deficit combined with other predisposing factors.Papilloma: A circumscribed benign epithelial tumor projecting from the surrounding surface; more precisely, a benign epithelial neoplasm consisting of villous or arborescent outgrowths of fibrovascular stroma covered by neoplastic cells. (Stedman, 25th ed)Restriction Mapping: Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.Vaccines, Edible: Vaccines or candidate vaccines derived from edible plants. Transgenic plants (PLANTS, TRANSGENIC) are used as recombinant protein production systems and the edible plant tissue functions as an oral vaccine.Organ Size: The measurement of an organ in volume, mass, or heaviness.Amyotrophic Lateral Sclerosis: A degenerative disorder affecting upper MOTOR NEURONS in the brain and lower motor neurons in the brain stem and SPINAL CORD. Disease onset is usually after the age of 50 and the process is usually fatal within 3 to 6 years. Clinical manifestations include progressive weakness, atrophy, FASCICULATION, hyperreflexia, DYSARTHRIA, dysphagia, and eventual paralysis of respiratory function. Pathologic features include the replacement of motor neurons with fibrous ASTROCYTES and atrophy of anterior SPINAL NERVE ROOTS and corticospinal tracts. (From Adams et al., Principles of Neurology, 6th ed, pp1089-94)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.Globins: A superfamily of proteins containing the globin fold which is composed of 6-8 alpha helices arranged in a characterstic HEME enclosing structure.Zebrafish Proteins: Proteins obtained from the ZEBRAFISH. Many of the proteins in this species have been the subject of studies involving basic embryological development (EMBRYOLOGY).Islets of Langerhans: Irregular microscopic structures consisting of cords of endocrine cells that are scattered throughout the PANCREAS among the exocrine acini. Each islet is surrounded by connective tissue fibers and penetrated by a network of capillaries. There are four major cell types. The most abundant beta cells (50-80%) secrete INSULIN. Alpha cells (5-20%) secrete GLUCAGON. PP cells (10-35%) secrete PANCREATIC POLYPEPTIDE. Delta cells (~5%) secrete SOMATOSTATIN.Nerve Degeneration: Loss of functional activity and trophic degeneration of nerve axons and their terminal arborizations following the destruction of their cells of origin or interruption of their continuity with these cells. The pathology is characteristic of neurodegenerative diseases. Often the process of nerve degeneration is studied in research on neuroanatomical localization and correlation of the neurophysiology of neural pathways.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Muscle, Skeletal: A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.Growth Hormone: A polypeptide that is secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Growth hormone, also known as somatotropin, stimulates mitosis, cell differentiation and cell growth. Species-specific growth hormones have been synthesized.RNA, Plant: Ribonucleic acid in plants having regulatory and catalytic roles as well as involvement in protein synthesis.Gossypium: A plant genus of the family MALVACEAE. It is the source of COTTON FIBER; COTTONSEED OIL, which is used for cooking, and GOSSYPOL. The economically important cotton crop is a major user of agricultural PESTICIDES.Maze Learning: Learning the correct route through a maze to obtain reinforcement. It is used for human or animal populations. (Thesaurus of Psychological Index Terms, 6th ed)Agrobacterium tumefaciens: A species of gram-negative, aerobic bacteria isolated from soil and the stems, leafs, and roots of plants. Some biotypes are pathogenic and cause the formation of PLANT TUMORS in a wide variety of higher plants. The species is a major research tool in biotechnology.Mammary Neoplasms, Animal: Tumors or cancer of the MAMMARY GLAND in animals (MAMMARY GLANDS, ANIMAL).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.Chromosomes, Artificial, Yeast: Chromosomes in which fragments of exogenous DNA ranging in length up to several hundred kilobase pairs have been cloned into yeast through ligation to vector sequences. These artificial chromosomes are used extensively in molecular biology for the construction of comprehensive genomic libraries of higher organisms.Glial Fibrillary Acidic Protein: An intermediate filament protein found only in glial cells or cells of glial origin. MW 51,000.RNA Interference: A gene silencing phenomenon whereby specific dsRNAs (RNA, DOUBLE-STRANDED) trigger the degradation of homologous mRNA (RNA, MESSENGER). The specific dsRNAs are processed into SMALL INTERFERING RNA (siRNA) which serves as a guide for cleavage of the homologous mRNA in the RNA-INDUCED SILENCING COMPLEX. DNA METHYLATION may also be triggered during this process.Stem Cells: Relatively undifferentiated cells that retain the ability to divide and proliferate throughout postnatal life to provide progenitor cells that can differentiate into specialized cells.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.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.Disease Progression: The worsening of a disease over time. This concept is most often used for chronic and incurable diseases where the stage of the disease is an important determinant of therapy and prognosis.Homozygote: An individual in which both alleles at a given locus are identical.Immunoblotting: Immunologic method used for detecting or quantifying immunoreactive substances. The substance is identified by first immobilizing it by blotting onto a membrane and then tagging it with labeled antibodies.Tauopathies: Neurodegenerative disorders involving deposition of abnormal tau protein isoforms (TAU PROTEINS) in neurons and glial cells in the brain. Pathological aggregations of tau proteins are associated with mutation of the tau gene on chromosome 17 in patients with ALZHEIMER DISEASE; DEMENTIA; PARKINSONIAN DISORDERS; progressive supranuclear palsy (SUPRANUCLEAR PALSY, PROGRESSIVE); and corticobasal degeneration.Salt-Tolerance: The ability of organisms to sense and adapt to high concentrations of salt in their growth environment.Genes, myc: Family of retrovirus-associated DNA sequences (myc) originally isolated from an avian myelocytomatosis virus. The proto-oncogene myc (c-myc) codes for a nuclear protein which is involved in nucleic acid metabolism and in mediating the cellular response to growth factors. Truncation of the first exon, which appears to regulate c-myc expression, is crucial for tumorigenicity. The human c-myc gene is located at 8q24 on the long arm of chromosome 8.Body Weight: The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.Gene Dosage: The number of copies of a given gene present in the cell of an organism. An increase in gene dosage (by GENE DUPLICATION for example) can result in higher levels of gene product formation. GENE DOSAGE COMPENSATION mechanisms result in adjustments to the level GENE EXPRESSION when there are changes or differences in gene dosage.Microscopy, Fluorescence: Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.Heart: The hollow, muscular organ that maintains the circulation of the blood.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.Cell Lineage: The developmental history of specific differentiated cell types as traced back to the original STEM CELLS in the embryo.Gene Silencing: Interruption or suppression of the expression of a gene at transcriptional or translational levels.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)Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.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.Behavior, Animal: The observable response an animal makes to any situation.

Deletion of a region that is a candidate for the difference between the deletion forms of hereditary persistence of fetal hemoglobin and deltabeta-thalassemia affects beta- but not gamma-globin gene expression. (1/44874)

The analysis of a number of cases of beta-globin thalassemia and hereditary persistence of fetal hemoglobin (HPFH) due to large deletions in the beta-globin locus has led to the identification of several DNA elements that have been implicated in the switch from human fetal gamma- to adult beta-globin gene expression. We have tested this hypothesis for an element that covers the minimal distance between the thalassemia and HPFH deletions and is thought to be responsible for the difference between a deletion HPFH and deltabeta-thalassemia, located 5' of the delta-globin gene. This element has been deleted from a yeast artificial chromosome (YAC) containing the complete human beta-globin locus. Analysis of this modified YAC in transgenic mice shows that early embryonic expression is unaffected, but in the fetal liver it is subject to position effects. In addition, the efficiency of transcription of the beta-globin gene is decreased, but the developmental silencing of the gamma-globin genes is unaffected by the deletion. These results show that the deleted element is involved in the activation of the beta-globin gene perhaps through the loss of a structural function required for gene activation by long-range interactions.  (+info)

Requirement for transcription factor NFAT in interleukin-2 expression. (2/44874)

The nuclear factor of activated T cells (NFAT) transcription factor is implicated in expression of the cytokine interleukin-2 (IL-2). Binding sites for NFAT are located in the IL-2 promoter. Furthermore, pharmacological studies demonstrate that the drug cyclosporin A inhibits both NFAT activation and IL-2 expression. However, targeted disruption of the NFAT1 and NFAT2 genes in mice does not cause decreased IL-2 secretion. The role of NFAT in IL-2 gene expression is therefore unclear. Here we report the construction of a dominant-negative NFAT mutant (dnNFAT) that selectively inhibits NFAT-mediated gene expression. The inhibitory effect of dnNFAT is mediated by suppression of activation-induced nuclear translocation of NFAT. Expression of dnNFAT in cultured T cells caused inhibition of IL-2 promoter activity and decreased expression of IL-2 protein. Similarly, expression of dnNFAT in transgenic mice also caused decreased IL-2 gene expression. These data demonstrate that NFAT is a critical component of the signaling pathway that regulates IL-2 expression.  (+info)

p38 mitogen-activated protein kinase can be involved in transforming growth factor beta superfamily signal transduction in Drosophila wing morphogenesis. (3/44874)

p38 mitogen-activated protein kinase (p38) has been extensively studied as a stress-responsive kinase, but its role in development remains unknown. The fruit fly, Drosophila melanogaster, has two p38 genes, D-p38a and D-p38b. To elucidate the developmental function of the Drosophila p38's, we used various genetic and pharmacological manipulations to interfere with their functions: expression of a dominant-negative form of D-p38b, expression of antisense D-p38b RNA, reduction of the D-p38 gene dosage, and treatment with the p38 inhibitor SB203580. Expression of a dominant-negative D-p38b in the wing imaginal disc caused a decapentaplegic (dpp)-like phenotype and enhanced the phenotype of a dpp mutant. Dpp is a secretory ligand belonging to the transforming growth factor beta superfamily which triggers various morphogenetic processes through interaction with the receptor Thick veins (Tkv). Inhibition of D-p38b function also caused the suppression of the wing phenotype induced by constitutively active Tkv (TkvCA). Mosaic analysis revealed that D-p38b regulates the Tkv-dependent transcription of the optomotor-blind (omb) gene in non-Dpp-producing cells, indicating that the site of D-p38b action is downstream of Tkv. Furthermore, forced expression of TkvCA induced an increase in the phosphorylated active form(s) of D-p38(s). These results demonstrate that p38, in addition to its role as a transducer of emergency stress signaling, may function to modulate Dpp signaling.  (+info)

Ganglioneuromas and renal anomalies are induced by activated RET(MEN2B) in transgenic mice. (4/44874)

Multiple endocrine neoplasia type 2B (MEN2B) is an autosomal dominant syndrome characterized by the development of medullary thyroid carcinoma, pheochromocytomas, musculoskeletal anomalies and mucosal ganglioneuromas. MEN2B is caused by a specific mutation (Met918-->Thr) in the RET receptor tyrosine kinase. Different mutations of RET lead to other conditions including MEN2A, familial medullary thyroid carcinoma and intestinal aganglionosis (Hirschsprung disease). Transgenic mice were created using the dopamine beta-hydroxylase promoter to direct expression of RET(MEN2B) in the developing sympathetic and enteric nervous systems and the adrenal medulla. DbetaH-RET(MEN2B) transgenic mice developed benign neuroglial tumors, histologically identical to human ganglioneuromas, in their sympathetic nervous systems and adrenal glands. The enteric nervous system was not affected. The neoplasms in DbetaH-RET(MEN2B) mice were similar to benign neuroglial tumors induced in transgenic mice by activated Ras expression under control of the same promoter. Levels of phosphorylated MAP kinase were not increased in the RET(MEN2B)-induced neurolglial proliferations, suggesting that alternative pathways may play a role in the pathogenesis of these lesions. Transgenic mice with the highest levels of DbetaH-RET(MEN2B) expression, unexpectedly developed renal malformations analogous to those reported with loss of function mutations in the Ret gene.  (+info)

The five amino acid-deleted isoform of hepatocyte growth factor promotes carcinogenesis in transgenic mice. (5/44874)

Hepatocyte growth factor (HGF) is a polypeptide with mitogenic, motogenic, and morphogenic effects on different cell types including hepatocytes. HGF is expressed as two biologically active isotypes resulting from alternative RNA splicing. The roles of each HGF isoform in development, liver regeneration and tumorigenesis have not yet been well characterized. We report the generation and analysis of transgenic mice overexpressing the five amino acid-deleted variant of HGF (dHGF) in the liver by virtue of an albumin expression vector. These ALB-dHGF transgenic mice develop normally, have an enhanced rate of liver regeneration after partial hepatectomy, and exhibit a threefold higher incidence of hepatocellular carcinoma (HCC) beyond 17 months of age. Moreover, overexpression of dHGF dramatically accelerates diethyl-nitrosamine induced HCC tumorigenesis. These tumors arise faster, are significantly larger, more numerous and more invasive than those appearing in non-transgenic littermates. Approximately 90% of female dHGF-transgenic mice had multiple macroscopic HCCs 40 weeks after injection of DEN; whereas the non-transgenic counterparts had only microscopic nodules. Liver tumors and cultured tumor cell lines from dHGF transgenics showed high levels of HGF and c-Met mRNA and protein. Together, these results reveal that in vivo dHGF plays an active role in liver regeneration and HCC tumorigenesis.  (+info)

A concise promoter region of the heart fatty acid-binding protein gene dictates tissue-appropriate expression. (6/44874)

The heart fatty acid-binding protein (HFABP) is a member of a family of binding proteins with distinct tissue distributions and diverse roles in fatty acid metabolism, trafficking, and signaling. Other members of this family have been shown to possess concise promoter regions that direct appropriate tissue-specific expression. The basis for the specific expression of the HFABP has not been previously evaluated, and the mechanisms governing expression of metabolic genes in the heart are not completely understood. We used transient and permanent transfections in ventricular myocytes, skeletal myocytes, and nonmyocytic cells to map regulatory elements in the HFABP promoter, and audited results in transgenic mice. Appropriate tissue-specific expression in cell culture and in transgenic mice was dictated by 1.2 kb of the 5'-flanking sequence of FABP3, the HFABP gene. Comparison of orthologous murine and human genomic sequences demonstrated multiple regions of near-identity within this promoter region, including a CArG-like element close to the TATA box. Binding and transactivation studies demonstrated that this element can function as an atypical myocyte enhancer-binding factor 2 site. Interactions with adjacent sites are likely to be necessary for fully appropriate, tissue-specific, developmental and metabolic regulation.  (+info)

Reversal of hyperlipidaemia in apolipoprotein C1 transgenic mice by adenovirus-mediated gene delivery of the low-density-lipoprotein receptor, but not by the very-low-density-lipoprotein receptor. (7/44874)

We have shown previously that human apolipoprotein (apo)C1 transgenic mice exhibit hyperlipidaemia, due primarily to an impaired clearance of very-low-density lipoprotein (VLDL) particles from the circulation. In the absence of at least the low-density-lipoprotein receptor (LDLR), it was shown that APOC1 overexpression in transgenic mice inhibited the hepatic uptake of VLDL via the LDLR-related protein. In the present study, we have now examined the effect of apoC1 on the binding of lipoproteins to both the VLDL receptor (VLDLR) and the LDLR. The binding specificity of the VLDLR and LDLR for apoC1-enriched lipoprotein particles was examined in vivo through adenovirus-mediated gene transfer of the VLDLR and the LDLR [giving rise to adenovirus-containing (Ad)-VLDLR and Ad-LDLR respectively] in APOC1 transgenic mice, LDLR-deficient (LDLR-/-) mice and wild-type mice. Remarkably, Ad-VLDLR treatment did not reduce hyperlipidaemia in transgenic mice overexpressing human APOC1, irrespective of both the level of transgenic expression and the presence of the LDLR, whereas Ad-VLDLR treatment did reverse hyperlipidaemia in LDLR-/- and wild-type mice. On the other hand, Ad-LDLR treatment strongly decreased plasma lipid levels in these APOC1 transgenic mice. These results suggest that apoC1 inhibits the clearance of lipoprotein particles via the VLDLR, but not via the LDLR. This hypothesis is corroborated by in vitro binding studies. Chinese hamster ovary (CHO) cells expressing the VLDLR (CHO-VLDLR) or LDLR (CHO-LDLR) bound less APOC1 transgenic VLDL than wild-type VLDL. Intriguingly, however, enrichment with apoE enhanced dose-dependently the binding of wild-type VLDL to CHO-VLDLR cells (up to 5-fold), whereas apoE did not enhance the binding of APOC1 transgenic VLDL to these cells. In contrast, for binding to CHO-LDLR cells, both wild-type and APOC1 transgenic VLDL were stimulated upon enrichment with apoE. From these studies, we conclude that apoC1 specifically inhibits the apoE-mediated binding of triacylglycerol-rich lipoprotein particles to the VLDLR, whereas apoC1-enriched lipoproteins can still bind to the LDLR. The variability in specificity of these lipoprotein receptors for apoC1-containing lipoprotein particles provides further evidence for a regulatory role of apoC1 in the delivery of lipoprotein constituents to different tissues on which these receptors are located.  (+info)

Overexpression of spermidine/spermine N1-acetyltransferase under the control of mouse metallothionein I promoter in transgenic mice: evidence for a striking post-transcriptional regulation of transgene expression by a polyamine analogue. (8/44874)

We recently generated a transgenic mouse line overexpressing spermidine/spermine N1-acetyltransferase (SSAT) gene under its own promoter. The tissue polyamine pools of these animals were profoundly affected and the mice were hairless from early age. We have now generated another transgenic-mouse line overexpressing the SSAT gene under the control of a heavy-metal-inducible mouse metallothionein I (MT) promoter. Even in the absence of heavy metals, changes in the tissue polyamine pools indicated that a marked activation of polyamine catabolism had occurred in the transgenic animals. As with the SSAT transgenic mice generated previously, the mice of the new line (MT-SSAT) suffered permanent hair loss, but this occurred considerably later than in the previous SSAT transgenic animals. Liver was the most affected tissue in the MT-SSAT transgenic animals, revealed by putrescine overaccumulation, significant decrease in spermidine concentration and >90% reduction in the spermine pool. Even though hepatic SSAT mRNA accumulated to massive levels in non-induced transgenic animals, SSAT activity was only moderately elevated. Administration of ZnSO4 further elevated the level of hepatic SSAT message and induced enzyme activity, but not more than 2- to 3-fold. Treatment of the transgenic animals with the polyamine analogue N1,N11-diethylnorspermine (DENSPM) resulted in an immense induction, more than 40000-fold, of enzyme activity in the liver of transgenic animals, and minor changes in the SSAT mRNA level. Liver spermidine and spermine pools were virtually depleted within 1-2 days in response to the treatment with the analogue. The treatment also resulted in a marked mortality (up to 60%) among the transgenic animals which showed ultrastructural changes in the liver, most notably mitochondrial swelling, one of the earliest signs of cell injury. These results indicated that, even without its own promoter, SSAT is powerfully induced by the polyamine analogue through a mechanism that appears to involve a direct translational and/or heterogenous nuclear RNA processing control. It is likewise significant that overexpression of SSAT renders the animals extremely sensitive to polyamine analogues.  (+info)

  • Spleen cells from the mice immunized with ret proteins were highly proliferated in vitro by the stimulation of ret proteins. (fujita-hu.ac.jp)
  • Conclusions Our results revealed anxiety-related traits and locomotor differences between transgenic mice expressing constitutive active MAPKAPK5 and control littermates. (uit.no)
  • Among these mouse models, Lemonnier laboratory has created the new generation of humanized HLA-transgenic mice like the HLA-A*0201/DRB1*0101 (A2/DR1) mouse model. (oncotarget.com)
  • Since little remains known about the MAPK-Activated Protein Kinase, MAPKAPK5, we constructed the first MAPKAPK knockin mouse model, using a constitutive active variant of MAPKAPK5 and analyzed the resulting mice for changes in anxiety-related behaviour. (uit.no)
  • Modulation of Alzheimer-like synaptic and cholinergic deficits in transgenic mice by human apolipoprotein E depends on isoform, aging, and overexpression of amyloid β peptides but not on plaque formation," Journal of Neuroscience , vol. 22, no. 24, pp. 10539-10548, 2002. (hindawi.com)
  • Human APOE isoform-dependent effects on brain β -amyloid levels in PDAPP transgenic mice," Journal of Neuroscience , vol. 29, no. 21, pp. 6771-6779, 2009. (hindawi.com)
  • Reprogramming cells within live mice yields a new type of induced pluripotent stem cell. (the-scientist.com)
  • Capecchi, M.R. (2005) Gene targeting in mice: functional analysis of the mammalian genome for the twenty-first century. (springer.com)
  • 1. A transgenic mouse, whose genome comprises an indicator gene under the control of a transcriptional regulatory element, wherein said transcriptional regulatory element comprises a MEF2 binding site and said indicator gene is (a) expressed in embryonic cardiac tissue, (b) not expressed in adult cardiac tissue, and (c) expressed in adult cardiac tissue in response to hypertrophic signals. (google.com)
  • To elucidate pathological roles of the virus in disease, transgenic mice were produced that carry the HTLV-I genome. (sciencemag.org)
  • The HBV Tg05 mouse line, which contains the 1.3-mer HBV genome and productively replicates HBV in the liver ( 21 ), was crossed with the mouse line that contains the floxed Atg5 gene (Atg5 f/f ). (asm.org)
  • This study engineered an hCAR-BAC-transgenic (hCAR-TG) mouse model by integrating the 8.5-kbp hCAR gene as well as 73-kbp upstream and 91-kbp downstream human genomic DNA into the genome of CAR-null mice. (ovid.com)
  • The first involves pronuclear injection into a single cell of the mouse embryo, where it will randomly integrate into the mouse genome. (wikipedia.org)
  • Introduction of foreign DNA into the mouse germ line is considered a major technical advancement in the fields of developmental biology and genetics. (springer.com)
  • In an attempt to determine the susceptibility of haploid, round spermatids to neoplastic transformation by this oncogene, transgenic mice were generated that harbored a chimeric gene composed of the SV40 T-antigen genes fused to the 5' and 3' flanking sequences of the mouse protamine 1 gene. (pnas.org)
  • In Tg(PrP,ΔGPI) mice, disease onset could be accelerated either by inoculation with brain homogenate prepared from spontaneously ill animals or by coexpression of membrane-anchored, full-length PrP C . In contrast, coexpression of N-terminally truncated PrP(Δ23-88) did not affect disease progression. (pnas.org)
  • Remarkably, disease from ill Tg(PrP,ΔGPI) mice transmitted to mice expressing wild-type PrP C , indicating the spontaneous generation of prions. (pnas.org)
  • Though the requirement of PrP C in disease pathogenesis is known, the function of PrP C in nondiseased tissue remains enigmatic because Prnp 0/0 mice exhibit only subtle or disputed phenotypic deficits, arguing that PrP C is largely dispensable for proper neuronal function ( 3 ). (pnas.org)
  • Bradley, A, van der Weyden, L. (2006) Mouse: Chromosome Engineering for Modeling Human Disease. (springer.com)
  • In this study, we examined collateral formation in peripheral arterial disease (PAD) model in Lp(a) transgenic mice. (ahajournals.org)
  • A team at the Spanish National Cancer Research Centre (CNIO) led by Mar-a Blasco has successfully created a transgenic mouse model that simulates the disease in humans. (news-medical.net)
  • A transgenic mouse developed at Cincinnati Children's to model the deadly childhood immune disease HLH (hemophagocytic lymphohistiocytosis) may play a key role in saving lives during the COVID-19 virus pandemic. (news-medical.net)
  • He also noticed that severe COVID-19 disease clinical manifestations are very similar to those seen in transgenic laboratory mice created to faithfully mimic human secondary HLH in the lab. (news-medical.net)
  • Disease resistance in DQ6 transgenic mice was associated with reduced synthesis of anti-AChR IgG, IgG2b, and IgG2c Ab's and reduced IL-2 and IFN-γ secretion by H-AChR- and peptide α320-337-specific lymphocytes. (jci.org)
  • While minor differences in weight fluctuation were noted between male and female mice after infection, the study did not indicate that gender played a major role in SARS-CoV-2 infectivity or disease progression. (newswise.com)
  • This study is the first to identify the amount of virus necessary during an initial exposure for the transgenic mice to develop severe COVID-19 disease. (newswise.com)
  • In addition to establishing the K18 hACE2 transgenic mouse model supplied by The Jackson Laboratory, researchers also found these transgenic mice were the most susceptible to severe COVID-19 disease progression and produced what is known as a chemokine storm. (newswise.com)
  • A proportion of A51 mice spontaneously develop AIG by 10 wk of age, with a disease characterized by eosinophilic infiltration of the gastric mucosa and Th2 differentiation of transgenic T cells in the gastric lymph node. (jimmunol.org)
  • Autoimmune gastritis (AIG) is commonly observed in d3Tx BALB/c mice and resembles the human disease pernicious anemia, in that the effector T cells and autoantibodies recognize the α and β subunits of the gastric parietal cell H/K-ATPase ( 11 , 12 ). (jimmunol.org)
  • VavP- Bcl2 mice also had a propensity to develop kidney disease of the autoimmune type. (bloodjournal.org)
  • Effects of Human Alpha-Synuclein A53T-A30P Mutations on SVZ and Local Olfactory Bulb Cell Proliferation in a Transgenic Rat Model of Parkinson Disease. (genoway.com)
  • Mice culled at 344 and 468 d had clinical prion disease. (cdc.gov)
  • The mouse culled at 720 d had clinical prion disease. (cdc.gov)
  • Two mice with clinical prion disease were culled at 558 and 749 d. (cdc.gov)
  • All mice had clinical prion disease. (cdc.gov)
  • Combined hyperlipidemia in transgenic mice overexpressing human apolipoprotein Cl. (jci.org)
  • We have generated transgenic mice over-expressing human apolipoprotein CI (apo CI) using the native gene joined to the downstream 154-bp liver-specific enhancer that we defined for apo E. Human apo CI (HuCI)-transgenic mice showed elevation of plasma triglycerides (mg/dl) compared to controls in both the fasted (211 +/- 81 vs 123 +/- 52, P = 0.0001) and fed (265 +/- 105 vs 146 +/- 68, P (jci.org)
  • Spontaneous mutations at the mouse Fused (Fu) locus cause dominant skeletal and neurological defects and recessive lethal embryonic defects including neuroectodermal abnormalities and axial duplications. (genetics.org)
  • A genomic probe from the wild-type H epsilon 46 locus detected a transcript that is disrupted by the transgenic insertion, representing a candidate for the wild-type allele of Fused. (genetics.org)
  • The corneal lesion observed in T27aT15 mice most closely resembles posterior polymorphous corneal dystrophy and might result from the disruption of the equivalent mouse locus. (bmj.com)
  • Conclusions -This study shows that in APOE*3-Leiden mice, duration of an HFC diet is associated with (1) a craniocaudal progression of lesion development and (2) an increased complexity of atherosclerotic lesions. (ahajournals.org)
  • Affected male mice had degenerative testicular lesions, and their sperm was immotile. (ingentaconnect.com)
  • Nonpolycystic K14 control male mice bred well, had no testicular lesions, and had appropriate sperm motility. (ingentaconnect.com)
  • This paper presents the first comprehensive histopathological characterization of transgenic PyV-mT hyperplasias together with classical transplantation experiments designed to test the growth potential of these lesions. (aacrjournals.org)
  • The PG-1 transgenic mice had significantly lower bacterial loads in their lungs and reduced numbers of pulmonary pathological lesions. (scialert.net)
  • The implantation of the Btc transgenic mice was delayed, but this was not the reason for the litter size reduction, because the mean number of total embryos either attached or recovered from the uterus of transgenic females was already markedly reduced when compared to the number of embryos present in the uterus of control females. (uni-muenchen.de)
  • In the developing mouse hippocampus, intrinsic neuronal excitability does not alter CA3 neuron development but regulates spine formation and synaptic transmission in CA1 neurons. (biologists.org)
  • These mice express optogenetic probes, such as enhanced halorhodopsin or several different versions of channelrhodopsins, behind various neuron-specific promoters. (broadinstitute.org)
  • In the present short paper, we summarize the current achievements of modeling neuron loss in transgenic mice based on APP/A β overexpression. (pubmedcentralcanada.ca)
  • To determine whether the enhancement is a general outcome of splicing or is dependent on the particular intron, we also produced equivalent transgenics carrying the widely used simian virus 40 small-t intron. (asm.org)
  • Previous attempts to culture PGCs from mice and humans produced embryonic germ cells that look and act like embryonic stem cells. (rxpgnews.com)
  • In this study, scientists showed the K18 hACE2 transgenic mice not only succumbed to the infection but showed systemic (multiple organ) infection with significant virus detected in the nasal passages, lungs, and brain - all organs greatly impacted by SARS-CoV-2 in humans. (newswise.com)
  • What makes these mice particularly interesting, say the researchers, is that they exhibit sex differences in the development of cardiac hypertrophy similar to those in humans. (bio-medicine.org)
  • and (3) major hCAR mRNA SVs increase markedly in postnatal livers of hCAR-TG mice, which mimics the ontogeny of CAR mRNA in humans. (ovid.com)
  • Takashima's team also reports weakened neural activity in the hippocampi of their transgenic mice, which they attribute to a smaller number of functional neurons, as well as impaired performance in two rodent behavioral tests. (alzforum.org)
  • how do I run behavioral assays to find out what's wrong with my mouse? (wiley.com)
  • to discover the wealth of mouse behavioral tasks and to get the guidance you need to select the best methods and necessary controls. (wiley.com)
  • Neurodevelopment and Neurodegeneration" discusses mouse behavioral tasks relevant to neurodevelopmental diseases, such as mental retardation and autism, and to neurodegenerative diseases, such as Alzheimers, Parkinsons, Huntingtons, and amyotrophic lateral sclerosis. (wiley.com)
  • Behavioral Phenotyping of Transgenic and Knockout Mice, Second Edition has been written in Dr. Crawley's private capacity, outside of her professional position at the National Institutes of Health. (wiley.com)
  • The team at Texas Biomed, led by Dr. Luis Martínez-Sobrido, Dr. Jordi B. Torrelles and Dr. Joanne Turner, showed detection of virus in the nasal passages, lungs and brain of the K18 hACE2 transgenic mice. (newswise.com)
  • Abnormal cardiac inflow patterns during postnatal development in a mouse model of Holt-Oram syndrome," American Journal of Physiology , vol. 289, no. 3, pp. (hindawi.com)
  • In a developmental study, transgenic mice were treated with GCV during the first postnatal week, with evaluation at P19. (jneurosci.org)
  • One transgenic line expressing low hVEGF levels showed mild clinical changes such as focal fluorescein leakage, microaneurysms, venous tortuosity, capillary non-perfusion and minor neovascularisation, which remained stable up to 3 months postnatal. (ovid.com)
  • Using simultaneous whole-cell monitoring of ionic currents and Cl-dependent fluorescence, we determined that the apparent EC 50 for Cl i was 46 mM, indicating that this line is appropriate for measuring neuronal [Cl i ] in postnatal mice. (frontiersin.org)
  • Impaired fertility in transgenic mice overexpressing Betacellulin Peptide growth factors regulate many cellular functions by autocrine, paracrine, juxtacrine or endocrine mechanisms. (uni-muenchen.de)