PAF1 cDNA Clone – Paf1, RNA Polymerase II Associated Factor, Homolog (S. Cerevisiae) (Human)

This gene encodes a subunit of the polymerase associated factor (PAF1) complex. The PAF1 complex interacts with RNA polymerase II and plays a role in transcription elongation as well as histone modifications including ubiquitylation and methylation. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Feb 2012]

PAF1: Component of the PAF1 complex (PAF1C) which has multiple functions during transcription by RNA polymerase II and is implicated in regulation of development and maintenance of embryonic stem cell pluripotency. PAF1C associates with RNA polymerase II through interaction with POLR2A CTD non- phosphorylated and 'Ser-2'- and 'Ser-5'-phosphorylated forms and is involved in transcriptional elongation, acting both indepentently and synergistically with TCEA1 and in cooperation with the DSIF complex and HTATSF1. PAF1C is required for transcription of Hox and Wnt target genes. PAF1C is involved in hematopoiesis and stimulates transcriptional activity of MLL1; it promotes leukemogenesis though association with MLL-rearranged oncoproteins, such as MLL-MLLT3/AF9 and MLL-MLLT1/ENL. PAF1C is involved in histone modifications such as ubiquitination of histone H2B and methylation on histone H3 'Lys-4' (H3K4me3). PAF1C recruits the RNF20/40 E3 ubiquitin-protein ligase complex and the E2 enzyme UBE2A or UBE2B to chromatin which mediate monoubiquitination of 'Lys-120' of histone H2B (H2BK120ub1); UB2A/B-mediated H2B ubiquitination is proposed to be coupled to transcription. PAF1C is involved in mRNA 3' end formation probably through association with cleavage and poly(A) factors. In case of infection by influenza A strain H3N2, PAF1C associates with viral NS1 protein, thereby regulating gene transcription. Connects PAF1C with the RNF20/40 E3 ubiquitin-protein ligase complex. Involved in polyadenylation of mRNA precursors. Has oncogenic activity in vivo and in vitro. Belongs to the PAF1 family. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: Tumor suppressor; Transcription regulation

Chromosomal Location of Human Ortholog: 19q13.1

Cellular Component: cell junction; cytoplasm; membrane; nucleoplasm

Molecular Function: protein binding

Biological Process: endodermal cell fate commitment; histone H2B ubiquitination; histone monoubiquitination; mRNA polyadenylation; negative regulation of myeloid cell differentiation; negative regulation of transcription from RNA polymerase II promoter; nucleosome positioning; positive regulation of histone methylation; positive regulation of mRNA 3'-end processing; positive regulation of RNA elongation from RNA polymerase II promoter; positive regulation of transcription from RNA polymerase II promoter