Cleavage and polyadenylation specificity factor subunit 4 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
that in humans is encoded by the ''CPSF4''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
Inhibition of the nuclear export of poly(A)-containing
mRNA
In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of Protein biosynthesis, synthesizing a protein.
mRNA is ...
s caused by the
influenza A virus
''Influenza A virus'' (''Alphainfluenzavirus influenzae'') or IAV is the only species of the genus ''Alphainfluenzavirus'' of the virus family '' Orthomyxoviridae''. It is a pathogen with strains that infect birds and some mammals, as well as c ...
NS1 protein requires its effector domain. The NS1 effector domain functionally interacts with the cellular 30 kDa subunit of cleavage and
polyadenylation
Polyadenylation is the addition of a poly(A) tail to an RNA transcript, typically a messenger RNA (mRNA). The poly(A) tail consists of multiple adenosine monophosphates; in other words, it is a stretch of RNA that has only adenine bases. In euka ...
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
Cleavage and polyadenylation specificity factor (CPSF) is involved in the Bond cleavage, cleavage of the 3' signaling region from a newly synthesized pre-messenger RNA (pre-mRNA) molecule in the process of transcription (genetics), gene transcript ...
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
A protein isoform, or "protein variant", is a member of a set of highly similar proteins that originate from a single gene and are the result of genetic differences. While many perform the same or similar biological roles, some isoforms have uniqu ...
have been described for this gene.
References
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