A cDNA encoding RAP74, a general initiation factor for transcription by RNA polymerase II

Abstract
RAP30/74 (also known as TFIIF (refs 1, 2), βΓ (ref. 3) and FC (ref. 4)) is one of several general factors required for initiation by RNA polymerase II (reviewed in refs 5–7). The small RAP30 subunit of RAP30/74 binds directly to polymerase and appears structurally and functionally homologous to bacterial sigma factors in their RNA polymerase-binding region8–10. RAP30/74 or recombinant RAP30 suppresses nonspecific binding of RNA polymerase II to DNA (refs 10,11) and is required for RNA polymerase II to assemble stably into a preinitiation complex containing promoter DNA and the general factors TFIID, TFIIA and TFIIB (refs 2,12, 13); both RAP30 and RAP74 are physical components of the preinitiation complex2. A complementary DNA encoding human RAP30 has been isolated8, and here we report the isolation of a cDNA encoding human RAP74. RAP30 and RAP74 produced in Escherichia coli can be used in place of natural human RAP30/74 to direct accurate transcription initiation by RNA polymerase II In vitro.