RAP74

RAP74, also known as the 74-kilodalton subunit of transcription factor IIF (TFIIF), is a protein that in humans is encoded by the GTF2F2 gene and is conserved across many eukaryotes. It forms a functional heterodimer with the RAP30 subunit (GTF2F1) to comprise the TFIIF complex that associates with RNA polymerase II.

In transcription initiation, TFIIF plays a role in promoter recognition and assembly of the preinitiation complex. RAP74 helps recruit RNA polymerase II to promoter regions together with other general transcription factors such as TFIIB and TBP. It contributes to stabilizing the initiation complex, reduces non-specific DNA binding by polymerase II, and facilitates promoter clearance and transition into productive elongation.

RAP74 is a nuclear protein with a molecular weight of approximately 74 kDa. Its structure includes regions that mediate interactions with RNA polymerase II and with the other TFIIF subunit, enabling cooperative function in transcription. The protein is part of a conserved transcriptional machinery found in a wide range of eukaryotic organisms.

Evolutionarily, RAP74/GTF2F2 is maintained across diverse species, reflecting a fundamental role in gene expression. In humans, perturbation of RAP74 function can disrupt transcription initiation and affect cellular transcriptional programs, though specific disease associations are not widely established.

Overall, RAP74 is a core component of the transcription initiation apparatus, enabling efficient recruitment and stabilization of RNA polymerase II at promoters through its partnership with RAP30 and other general transcription factors.