Kruppel-Like Transcription Factors: A family of zinc finger transcription factors that share homology with Kruppel protein, Drosophila. They contain a highly conserved seven amino acid spacer sequence in between their ZINC FINGER MOTIFS.Early Growth Response Transcription Factors: A family of transcription factors that are induced by GROWTH FACTORS and contain a highly conserved DNA-binding domain composed of three ZINC FINGER MOTIFS.Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.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.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.Trans-Activators: Diffusible gene products that act on homologous or heterologous molecules of viral or cellular DNA to regulate the expression of proteins.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.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.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.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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Transcriptional Activation: Processes that stimulate the GENETIC TRANSCRIPTION of a gene or set of genes.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.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.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.Cell Line: Established cell cultures that have the potential to propagate indefinitely.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.Basic Helix-Loop-Helix Transcription Factors: A family of DNA-binding transcription factors that contain a basic HELIX-LOOP-HELIX MOTIF.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.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.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.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.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.Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.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).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).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.Forkhead Transcription Factors: A subclass of winged helix DNA-binding proteins that share homology with their founding member fork head protein, Drosophila.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.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)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.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.Basic-Leucine Zipper Transcription Factors: A large superfamily of transcription factors that contain a region rich in BASIC AMINO ACID residues followed by a LEUCINE ZIPPER domain.