LEO1

LEO1, parafibromin form the PAF protein complex that associates with the RNA polymerase II subunit POLR2A and with a histone methyltransferase complex.

Full Name

LEO1 Homolog, Paf1/RNA Polymerase II Complex Component

Function

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 independently 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 KMT2A/MLL1; it promotes leukemogenesis through association with KMT2A/MLL1-rearranged oncoproteins, such as KMT2A/MLL1-MLLT3/AF9 and KMT2A/MLL1-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 (AC 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. Involved in polyadenylation of mRNA precursors. Connects PAF1C to Wnt signaling.

Biological Process

Endodermal cell fate commitmentISS:UniProtKB
Histone H2B ubiquitinationManual Assertion Based On ExperimentIDA:UniProtKB
Histone monoubiquitinationManual Assertion Based On ExperimentIDA:UniProtKB
mRNA polyadenylationManual Assertion Based On ExperimentIMP:UniProtKB
Negative regulation of myeloid cell differentiationManual Assertion Based On ExperimentIDA:UniProtKB
Positive regulation of mRNA 3'-end processingManual Assertion Based On ExperimentIMP:UniProtKB
Positive regulation of transcription elongation from RNA polymerase II promoterManual Assertion Based On ExperimentIBA:GO_Central
Stem cell population maintenanceManual Assertion Based On ExperimentIDA:UniProtKB
Transcription elongation from RNA polymerase II promoterManual Assertion Based On ExperimentIDA:GO_Central
Wnt signaling pathwayIEA:UniProtKB-KW

Cellular Location

Nucleus