Transcription factors are proteins that are required to initiate or regulate gene transcription in eukaryotic cells. General transcription factors are required for basal transcription of genes and participate in formation of the transcription-initiation complex. Many interact directly with RNA polymerase. Specific transcription factors stimulate or repress transcription of particular genes by binding to their coordinate regulatory sequence which promotes or blocks RNA polymerase binding respectively.
Transcription Factor Target Files
A defining feature of transcription factors is the presence of a DNA-binding domain (DBD) which attaches to a specific DNA sequence at a site adjacent to the regulated gene. Other molecules can affect transcription, for example histone deacetylase and DNA methyltransferase, but are not referred to as transcription factors as they lack a DBD.
Transcription factors have a vital role in gene expression, thus are involved in development, intercellular signaling and the cell cycle. Perturbations in transcription factor activity is associated with human diseases including various cancers and autoimmune diseases.