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.
Caravokyri
C
C
Department of Biological Sciences, University of Warwick, Coventry, U.K.
Pringle
C R
CR
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