Protein production rates of general transcription factors for RNA polymerase II. Top: schematic structure of the transcription initiation complex in yeast. Bottom: composition of basal transcription factors (after KEGG , accessed May 2014), along with the values of the protein production rate R for each subunit. R values correspond to the color intensity. Subunits forming other complexes (according to SGD , accessed May 2014) are marked by blue symbols explained on the left. Protein production rates are similar for the majority of TFIID and TFIIH components. Most of the observed discrepancies in R may be explained by an additional biological function of a subunit in other complexes.