The sequence similarity of reovirus sigma 3 protein to picornaviral proteases is unrelated to its role in mu 1 viral protein cleavage.
Recent data have shown that the reovirus sigma 3 protein is the only viral product required for proteolytic conversion of the viral mu 1 protein to mu 1C. In an effort to determine the importance of a sigma 3 region exhibiting sequence similarity to a functionally important region of picornaviral proteases, we analyzed proteins produced in COS cells cotransfected with expression vectors encoding mu 1 and either wild-type or mutated forms of sigma 3. This approach revealed that association with sigma 3 contributes to the stability of mu 1-related polypeptides (mu 1 + mu 1C), but conservation of the sigma 3 region related to picornaviral proteases is not required for proteolytic conversion of mu 1 to mu 1C.
Mabrouk
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T
Département de Microbiologie et Immunologie, Université de Montréal, Québec, Canada.
Lemay
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G
D000595:Amino Acid Sequence; D000818:Animals; D002213:Capsid / Q000378:metabolism*; D036022:Capsid Proteins; D002460:Cell Line; D002522:Chlorocebus aethiops; D010450:Endopeptidases / Q000737:chemistry; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011499:Protein Processing, Post-Translational; D016601:RNA-Binding Proteins; D012087:Reoviridae / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*
D036022:Capsid Proteins; D016601:RNA-Binding Proteins; D014764:Viral Proteins; C055356:mu1 protein, Reovirus; C053179:sigma protein 3, Reovirus; D010450:Endopeptidases