Send to

Choose Destination
Biochem Cell Biol. 1995 Mar-Apr;73(3-4):137-45.

Two basic motifs of reovirus sigma 3 protein are involved in double-stranded RNA binding.

Author information

Département de microbiologie et immunologie, Université de Montréal, Canada.


It has been reported that the sigma 3 protein of reovirus can exert an inhibitory effect on the cellular double-stranded RNA (dsRNA) activated protein kinase. Activation of this kinase is thought to be a general mechanism mediating a cellular antiviral response. This enzyme can also be activated upon transfection, resulting in translational inhibition of plasmid-encoded mRNAs. sigma 3 has an affinity for dsRNA postulated to be responsible for antikinase activity. In the present study, site-directed mutagenesis was performed on two basic regions previously suggested as dsRNA-binding motifs and the mutant sigma 3 proteins were then expressed in COS cells. These experiments revealed that both motifs are involved in sigma 3 attachment to RNA. Expression of the mutants lacking RNA-binding capability is stimulated by coexpression of another dsRNA-binding protein, the E3L vaccinia virus protein. These results support a model in which the attachment to dsRNA is directly responsible for the trans-stimulating effect of sigma 3 on expression of cotransfected genes.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Atypon
Loading ...
Support Center