Expression of Reovirus Type 3 (Dearing) σ1 and σs Polypeptides in Escherichia coli† Pelletier, Jerry and Nicholson, Robert and Bassel-Duby, Rhonda and Fields, Bernard N. and Sonenberg, Nahum,, 68, 135-145 (1987), doi = https://doi.org/10.1099/0022-1317-68-1-135, publicationName = Microbiology Society, issn = 0022-1317, abstract= SUMMARY The reovirus S1 gene codes for two polypeptides: σl and σs. In order to characterize the structure and function of the σl polypeptide, we have expressed the σ1 protein in Escherichia coli. The SI gene from mammalian reovirus type 3 (Dearing strain) and the variant K strain were subcloned into an expresssion vector containing the tac (trp-lac) promoter designed to express foreign gene products in E. coli efficiently. The hybrid plasmids, upon induction with isopropyl-β-d-thiogalactopyranoside, expressed two polypeptides that were detected by [35S]methionine labelling. One of the induced proteins had a relative molecular mass (M r) of approx. 46000 and corresponded to σl, as shown by immunoprecipitation with goat anti-reovirus antibody and a monoclonal antibody against σl, The second induced protein had a M r of approx. 12000 and was very similar to σs as judged by comparative tryptic peptide map analysis. Protein σl produced in E. coli was shown to be functional as judged from its ability to bind to mouse L fibroblasts. , language=, type=