The highly conserved RNA polymerase II transcription factor TFIID comprises the TATA box-binding protein (TBP) and a set of TBP-associated factors (TAFs), including TAF3. TAFs contribute to promoter recognition and selectivity and act as antiapoptotic factors. By EST database searching for sequences similar to the histone fold domain (HFD) of yeast Tafii47, followed by probing a HeLa cell cDNA library, Gangloff et al. (2001) obtained a partial cDNA encoding TAF3, which they termed TAFII140. The deduced 727-amino acid protein contains an N-terminal HFD and is highly homologous to mouse Tafii140. The 932-amino acid mouse protein has a C-terminal plant homeodomain (PHD) finger, and genomic database analysis suggested that this motif is present in human TAF3.