Purified anti-RNA Polymerase II Rpb4 Antibody, RNA Polymerase II RPB4, 2Y14,BioLegend,665106

Polymerase II (Pol II) is the central component of the basal RNA polymerase II transcription machinery. It is composed of mobile elements that move relative to each other. RPB4 is part of a subcomplex with RPB7 that binds to a pocket formed by RPB1, RPB2, and RPB6 at the base of the clamp element. The RBP4-RPB7 subcomplex seems to lock the clamp since RPB7 is in the closed conformation, which prevents double stranded DNA from entering the active site cleft. The RPB4-RPB7 subcomplex only binds single-stranded DNA and RNA. The RPB4-RPB7 subcomplex is necessary for promoter-directed transcription initiation, but is not required for recruitment of Pol II to active preinitiation complexes or transcription elongation and termination. The RPB4-RPB7 subcomplex recruits FCP1 to Pol II. This subcomplex is involved in DNA repairing of any damage in the transcribed strand. RPB4 is unnecessary in optimal growth conditions, but becomes essential during heat or cold shock and in nutrient depletion. It suppresses the RBP9-mediated transcription coupled repair (TCR) subpathway of nucleotide excision repair (NER), but facilitates the RAD26-mediated TCR subpathway. Under stress conditions, it is involved in mRNA export to the cytoplasm. RPB4 promotes or enhances the deadenylation process of specific mRNAs and may recruit PAT1 and the LSM1-7 complex to these mRNAs, stimulating their decapping and further decay.