The basal transcription factor TFIID plays a central role in the regulation of gene expression in Eukaryota and is a large protein complex composed of TATA box-binding protein (TBP) and 14 kinds of TBP-associated factors (TAF). TFIID directly recognizes and binds to different kinds of core promoter elements that localize near the transcription initiation site and forms a scaffold for the other basal transcription factors to assemble. At the same time, it transmits transcriptional activation signal originating from transcription regulating factors to RNA polymerase II. Taf4p is one of the subunits of TFIID and in the case of budding yeast, it is composed of 388 amino acid residues (aa). This protein contains histone folds in its interior and forms TAF octamer with Taf6p, Taf9p and Taf12p.
The product was prepared by immunizing rabbit with recombinant protein which was over-expressed in E. coli with a plasmid carrying the N-terminal domain of Taf4p protein (1-200aa) of budding yeast, and purified by chromatography.
Using this antiserum in Western blotting, the band of 48 kD corresponding to Taf4p was obtained from the extract of yeast cells.