<p>Transcription factor IIF (TFIIF), which is essential for eukaryotic transcription by RNA polymerase II. (PolII), consists of a heterodimer of Rap30 (beta) (<db_xref db="INTERPRO" dbkey="IPR003196"/>) and Rap74 (alpha) (<db_xref db="INTERPRO" dbkey="IPR008851"/>) subunits [<cite idref="PUB00014142"/>]. Rap30 and Rap74 have multiple domains that bind to PolII, TFIIB, TAF250 and DNA in interactions that are essential for transcription initiation and elongation. The N-terminal interactions domains of Rap30 and Rap74 are responsible for establishing the dimer interface between the two subunits, this interface being important for TFIIF function [<cite idref="PUB00011486"/>].</p>