Defective synthesis of envelope proteins by temperature-sensitive mutants representing complementation groups B and D of respiratory syncytial virus.
The phenotypes of two complementing temperature-sensitive (ts) mutants of respiratory syncytial (RS) virus indicate that the mutational lesions involve the attachment (G) and matrix (M) proteins of the viral envelope. Synthesis of the G protein was affected in cells infected with mutant tsA2 (complementation group B); the p50 precursor of the G protein was synthesized normally, but further maturation to the fully glycosylated form was defective at 39 degrees C. A non-ts alteration in the efficiency of cleavage of the F0 precursor to the F1 and F2 subunits of the fusion protein was also observed in tsA2-infected cells, which is consistent with the aberrant non-syncytial plaque morphology induced by tsA2 in certain cells. In cells infected with mutant tsN1 (complementation group D) the M protein disappeared from the soluble cytoplasmic fraction soon after synthesis at 39 degrees C and had a slightly decreased electrophoretic mobility. The M protein of non-ts revertants was stable at 39 degrees C, which links the defect in M protein stability with the tsN1 phenotype. However, the aberrant mobility phenotype remained, suggesting pseudoreversion. These results assign two of the eight complementation groups of ts mutants of RS virus.
Department of Biological Sciences, University of Warwick, Coventry, U.K.
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Caravokyri
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Pringle
D002460:Cell Line; D019204:GTP-Binding Proteins / Q000378:metabolism; D005816:Genetic Complementation Test; D007700:Kinetics; D009154:Mutation; D010641:Phenotype; D011233:Precipitin Tests; D011499:Protein Processing, Post-Translational; D012136:Respiratory Syncytial Viruses / Q000235:genetics* / Q000378:metabolism; D013696:Temperature; D014759:Viral Envelope Proteins / Q000096:biosynthesis*
D014759:Viral Envelope Proteins; D019204:GTP-Binding Proteins