Regulated, stable expression and nuclear presence of reovirus double-stranded RNA-binding protein sigma3 in HeLa cells.
Reovirus genome segment S4 codes for polypeptide sigma3, a major outer capsid component of virions and a double-stranded RNA (dsRNA)-binding protein implicated in viral cytopathogenesis. We have constructed a stable HeLa cell line (S4tTA) that produces functional sigma3 under tetracycline transactivator control. In the absence of tetracycline, S4tTA cells synthesized stable dsRNA-binding sigma3 that accumulated in the nucleus as well as in the cytoplasm. However, in induced S4tTA cells also expressing reovirus outer shell polypeptide mu1/mu1C, migration of sigma3 into the nucleus was blocked, probably as a result of formation of a complex with mu1/mu1C which was exclusively in the cytoplasm. Mutant analyses indicated a correlation between dsRNA-binding activity and nuclear entry of sigma3, suggesting an additional role(s) for this capsid protein in virus-cell interactions.
Yue
Z
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Graduate Program in Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, USA.
Shatkin
A J
AJ
D000595:Amino Acid Sequence; D036022:Capsid Proteins; D002467:Cell Nucleus / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D012330:RNA, Double-Stranded / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000032:analysis*; D012087:Reoviridae / Q000737:chemistry* / Q000502:physiology; D014764:Viral Proteins / Q000032:analysis* / Q000502:physiology
D036022:Capsid Proteins; D012330:RNA, Double-Stranded; D016601:RNA-Binding Proteins; D014764:Viral Proteins; C053179:sigma protein 3, Reovirus