SUMMARY PARAGRAPH for TAF4
TFIID is a transcription factor complex that is required for RNAPII-mediated transcription of protein-coding genes and some small nuclear RNAs (reviewed in 3). The complex is composed of Spt15p (TATA binding protein; TBP) and 14 TBP-associated factors (TAFs): Taf1p, Taf2p, Taf3p, Taf4p, Taf5p, Taf6p, Taf7p, Taf8p, Taf9p, Taf10p, Taf11p, Taf12p, Taf13p, Taf14p (4, 5). The TFIID complex is required for basal transcription, but some individual subunits regulate the activated transcription of a subset of genes (6, 7, 8, 9, 10).
Recognition of promoter DNA by the TFIID complex is required for the formation of the preinitiation complex (PIC) during transcription initiation (11, 12). The interaction between the TFIID complex and the promoter is stabilized by TFIIA (12, 13). The recruitment of TFIID to promoters is dependent on an upstream activating sequence in the promoter region (14).
A subset of the TAFs (Taf5p, Taf6p, Taf9p, Taf10p, and Taf12p) are subunits of both TFIID and the the Spt-Ada-Gcn5-acetyltransferase (SAGA) transcriptional regulatory complex, which functions in nucleosomal histone acetylation and chromatin-associated transcriptional activation or repression (15, 16, 17). The results of genome-wide studies indicate that TFIID functions primarily at the TATA-less promoters of stress-repressed housekeeping genes, representing about 90% of the yeast genome, while SAGA predominates at highly-regulated, stress-responsive TATA box-containing genes, representing about 10% of the genome (18, 19).
Last updated: 2009-10-02