UC Riverside

The general transcription factor II D (TFIID) nucleates the assembly of general transcription factors (GTF) and RNA polymerase II at the promoters to form the pre-initiation complex (PIC). TBP-associated factor I (TAF1), the scaffold of TFIID, not only interacts with other factors to stabilize the protein complex but also has several enzymatic activities.

In this study, genome-wide ChIP-on-chip analysis revealed that TAF1 recognizes and binds in vivo to more than 1,800 of core promoters. From the transcription profiling, 4,531 genes have been identified with more than 1.25 folds change in transcriptional level, including 2,780 genes with reduced transcription and 1,751 with an enhanced transcription level. Among TAF1 target genes, 53% of genes were directly down-regulated by TAF1, especially cyclins and cell cycle regulators. Genes such as members of the heat shock protein family were associated with direct TAF1 upregulation. This study suggests that TAF1 is essential protein and involved in various biological processes including cell cycle progression and stress response.