Transcription elongation by RNA polymerase II is regulated by the general elongation factor TFIIS. This factor stimulates RNA polymerase II to transcribe through regions of DNA that promote the formation of stalled ternary complexes. TFIIS is composed of three structural domains, termed I, II, and III. The two C-terminal domains (II and III), this domain and Pfam:PF01096 are required for transcription activity [1].

1: Elongation factor TFIIS contains three structural domains: solution structure of domain II. Morin PE, Awrey DE, Edwards AM, Arrowsmith CH; Proc Natl Acad Sci U S A 1996;93:10604-10608. PMID:8855225