RNA polymerase II transcription of Class II genes involves the TFIID transcription complex comprised of general factors, including TBP, TFIIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIG/J, and TFIIH, as well as gene-specific factors that include TAFs, which interact with regulatory protein activation domains to enhance transcription. A second group of cofactors includes PC1, PC2, and PC3, which have a strong positive influence on transcription. The combined action of general and gene-specific regulators encoded by Transcription Coactivator Genes enhances gene expression. (NCI) [ ]