Products of the porcine group C rotavirus NSP3 gene bind specifically to double-stranded RNA and inhibit activation of the interferon-induced protein kinase PKR.
The porcine group C rotavirus (Cowden strain) NSP3 protein (the group C equivalent of the group A gene 7 product, formerly called NS34) shares homology with known double-stranded RNA-binding proteins, such as the interferon-induced, double-stranded RNA-dependent protein kinase PKR. A clone of NSP3, expressed both in vitro and in COS-1 cells, led to the synthesis of minor amounts of a product with an M(r) of 45,000 (the expected full-length M(r) of NSP3) and major amounts of products with M(r)s of 38,000 and 8,000. Restriction enzyme digestion analysis prior to expression in vitro and amino-terminal sequence analysis suggest that the products with M(r)s of 38,000 and 8,000 are cleavage products of the protein with an M(r) of 45,000. The full-length protein and the product with an M(r) of 8,000, both of which contain the motif present in double-stranded RNA-binding proteins, bound specifically to double-stranded RNA. The products with M(r)s of 45,000 and 8,000 were also detected in Cowden strain-infected MA104 cells. NSP3 products expressed in COS-1 cells were capable of inhibiting activation of the double-stranded RNA-dependent protein kinase similar to other double-stranded RNA-binding proteins, and NSP3 products expressed in HeLa cells were capable of rescuing the replication of an interferon-sensitive deletion mutant of vaccinia virus.
Langland
J O
JO
Department of Microbiology, Arizona State University, Tempe 85287-2701.
Pettiford
S
S
Jiang
B
B
Jacobs
B L
BL
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D003001:Cloning, Molecular; D016384:Consensus Sequence; D004789:Enzyme Activation; D005814:Genes, Viral; D006367:HeLa Cells; D006801:Humans; D007372:Interferons / Q000494:pharmacology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012401:Rotavirus / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D013552:Swine; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019892:eIF-2 Kinase
C082740:NSP3 protein, Rotavirus; D012330:RNA, Double-Stranded; D016601:RNA-Binding Proteins; D017361:Viral Nonstructural Proteins; D007372:Interferons; D017346:Protein Serine-Threonine Kinases; D019892:eIF-2 Kinase