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Transcription Factor

Also known as:Trans-acting factorSequence-specific DNA-binding protein

A transcription factor is a protein that binds to specific DNA sequences in the promoter or enhancer regions of a gene to control the rate of transcription by RNA polymerase. These proteins act as molecular switches, either activating or repressing gene expression in response to developmental cues, environmental signals, or cellular needs. In humans, approximately 1,600 transcription factors have been identified, and their dysregulation is linked to cancers, developmental disorders, and metabolic diseases.

Classes of Transcription Factors and Their DNA-Binding Domains

ClassDNA-Binding DomainExampleFunction
Zinc FingerZinc-coordinated finger loopSP1Activates housekeeping genes
Helix-Turn-HelixAlpha-helical recognition helixHomeobox proteinsDevelopmental patterning
Leucine ZipperBasic region + leucine zipperAP-1 (Fos/Jun)Stress and growth response
Helix-Loop-HelixBasic HLH dimerisation domainMyoDMuscle differentiation
Nuclear ReceptorZinc finger + ligand-bindingEstrogen receptorHormone-regulated transcription

Interactive Tools

JASPAR Transcription Factor Database

Curated database of transcription factor binding profiles and motifs

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Khan Academy — Gene Regulation

Video lessons on transcription factors and gene regulation

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NCBI Gene Expression Resources

Search gene records including associated transcription factor data

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Ribbon diagram of a transcription factor protein bound to a double-stranded DNA molecule

Wikimedia Commons, CC BY-SA

Related Terms

Biology

Alternative Splicing

Alternative splicing is a regulated process during gene expression in which particular exons of a pre-mRNA transcript are included or excluded to generate multiple distinct mature mRNA isoforms from a single gene. This mechanism dramatically expands proteomic diversity; estimates suggest that over 95% of human multi-exon genes undergo alternative splicing, allowing a genome of ~20,000 genes to produce hundreds of thousands of protein variants. Mis-regulation of alternative splicing is implicated in many diseases including spinal muscular atrophy, various cancers, and neurological disorders.

From Latin "transcribere" (to copy across) and Latin "factor" (maker, from "facere" to make). The term came into use in the 1960s–1970s as molecular biologists characterised proteins that controlled RNA synthesis.

gene-regulationtranscriptionproteinpromotermolecular-biology