cleavage & polyadenylation specificity factor subunit 3; cleavage & polyadenylation specificity factor 73 kD subunit; CPSF 73 kD subunit; mRNA 3'-end-processing endonuclease CPSF-73 (CPSF3, CPSF73)
Jump to navigation
Jump to search
Function
- component of the CPSF complex involvef in pre-mRNA 3'-end formation
- has endonuclease activity;functions as mRNA 3'-end-processing endonuclease
- also involved in the histone 3'-end pre-mRNA processing
- U7 snRNP-dependent protein that induces both the 3'-endoribonucleolytic cleavage of histone pre-mRNAs & acts as a 5' to 3' exonuclease for degrading the subsequent downstream cleavage product (DCP) of mature histone mRNAs
- cleavage occurs after the 5'-ACCCA-3' sequence in the histone pre-mRNA leaving a 3'hydroxyl group on the upstream fragment containing the stem loop (SL) & 5' phosphate on the downstream cleavage product (DCP) starting with CU nucleotides
- the U7-dependent 5' to 3' exonuclease activity is processive & degrades the DCP RNA substrate even after complete removal of the U7-binding site
- binds to the downstream cleavage product (DCP) of histone pre-mRNAs & the cleaved DCP RNA
- substrate in a U7 snRNP dependent manner
- sumoylated on Lys-462, Lys-465 & Lys-545, preferentially by SUMO3
Cofactor: binds 2 Zn+2 per subunit
Structure
- belongs to the metallo-beta-lactamase superfamily RNA-metabolizing metallo-beta-lactamase-like family, CPSF3 subfamily