Transcription elongation: The ‘Foggy’ is lifting…

Eukaryotic messenger RNAs are synthesized by the multisubunit enzyme RNA polymerase II, aided by myriad cofactors that control different events in this multistep process. A complete round of transcription involves: the recruitment of polymerase and general transcription factors to the promoter, RNA chain initiation and polymerase escape from the promoter, RNA chain elongation, and finally termination with release of polymerase and nascent transcript from the DNA template [1]. Transcriptional elongation is far less well understood than initiation, though proteins have been identified that influence elongation in vivo and in vitro. The general transcription factors TFIIF and TFIIH stimulate both initiation and elongation. Other factors are specific regulators of elongation, and these include the polymerase II-associated protein TFIIS, modifiers of chromatin structure and sequence-specific transactivators such as HIV Tat [2,3]. A recent study [4] has now identified a specific regulator of elongation, dubbed Foggy, which appears to play an important role in the determination of cell fate.