Cleavage and Polyadenylation Specific Factor 4 (CPSF4) Human Recombinant Protein

Inhibition of the nuclear export of poly(A)-containing mRNAs caused by the influenza A virus NS1 protein requires its effector domain. The NS1 effector domain functionally interacts with the cellular 30 kDa subunit of cleavage and polyadenylation specific factor 4, an essential component of the 3' end processing machinery of cellular pre-mRNAs. In influenza virus-infected cells, the NS1 protein is physically associated with cleavage and polyadenylation specific factor 4, 30kD subunit. Binding of the NS1 protein to the 30 kDa protein in vitro prevents CPSF binding to the RNA substrate and inhibits 3' end cleavage and polyadenylation of host pre-mRNAs. Thus the NS1 protein selectively inhibits the nuclear export of cellular, and not viral, mRNAs. Multiple alternatively spliced transcript variants that encode different isoforms have been described for this gene. [provided by RefSeq, Jul 2008]

CPSF4: Component of the cleavage and polyadenylation specificity factor (CPSF) complex that play a key role in pre-mRNA 3'-end formation, recognizing the AAUAAA signal sequence and interacting with poly(A) polymerase and other factors to bring about cleavage and poly(A) addition. CPSF4 binds RNA polymers with a preference for poly(U). Belongs to the CPSF4/YTH1 family. 3 isoforms of the human protein are produced by alternative splicing.

Protein type: RNA processing; Mitochondrial

Chromosomal Location of Human Ortholog: 7q22.1

Cellular Component: nucleoplasm; mRNA cleavage and polyadenylation specificity factor complex

Molecular Function: zinc ion binding

Biological Process: modification by virus of host cellular process; virus-host interaction; modification by virus of host mRNA processing; viral infectious cycle; mRNA processing