BIOSYNTHESIS AND MORPHOGENESIS OF GROUP-C ROTAVIRUS IN SWINE TESTICULAR CELLS

Polypeptide synthesis and morphogenesis of a group C rotavirus (AmC- 1 ) adapted to a continuous swine testicular cell line was examined. SDS -PAGE analysis of S-35 methionine labeled infected cell lysates reveal ed 9 viral polypeptides (122, 98, 79, 78, 43, 41, 35, 24, and 20 kD). Viral polypeptide synthesis appeared to be maximal at 7-10 h post infe ction. Purified group C virus grown in the presence of trypsin was fou nd to contain seven structural polypeptides (122, 98, 79, 53, 43, 41, and 30 kD) by protein blotting and five polypeptides (98, 79, 78, 43, and 41 kD) by immunoprecipitation with a hyperimmune rabbit antisera. Tunicamycin treatment, Concanavalin A binding, protein blotting, endo- H treatment and H-2,H-6-mannose labeling suggested that group C rotavi rus contains one structural glycoprotein (41 kD) with a corresponding precursor mol. wt. of 37 kD and one not previously identified nonstruc tural glycoprotein (24 kD) with a corresponding precursor mol. wt. of less-than-or-equal-to 20 kD. Electron microscopy of infected swine tes ticular cells revealed an assembly process for group C rotavirus simil ar to group A, with single-shelled particles budding through the rough endoplasmic reticulum with concomitant acquisition of a transient mem brane.