TAF3 (TATA-box binding protein-associated factor 3) is a subunit of the TFIID complex, a critical component of the RNA polymerase II transcription machinery. As part of the TFIID complex, TAF3 plays a role in mediating promoter recognition and regulating transcription initiation. It is one of the TAF family proteins that interact with TBP (TATA-box binding protein) to stabilize DNA binding and recruit coactivators. Unlike some TAFs, TAF3 is not universally required for all RNA polymerase II-dependent transcription but exhibits gene-specific regulatory functions.
A key feature of TAF3 is its ability to bind histone H3 lysine 4 trimethylation (H3K4me3), a chromatin modification associated with active gene promoters, through its conserved PHD (plant homeodomain) zinc finger. This interaction links epigenetic marks to the core transcriptional machinery, facilitating the recruitment of TFIID to specific loci. TAF3 also participates in cellular differentiation processes, particularly in myogenesis and stem cell maintenance, by regulating lineage-specific genes.
TAF3 antibodies are essential tools for studying its localization, protein-protein interactions, and transcriptional regulatory mechanisms. They are widely used in techniques like chromatin immunoprecipitation (ChIP), Western blotting, and immunofluorescence to investigate TAF3's role in development, cell cycle progression, and diseases such as cancer. Dysregulation of TAF3 has been implicated in tumorigenesis, with altered expression observed in several malignancies.