Molecular genetic evidence that the hydrophobic anchors of glycoproteins E2 and E1 interact during assembly of alphaviruses.
Chimeric alphaviruses in which the 6K and glycoprotein E1 moieties of Sindbis virus are replaced with those of Ross River virus grow very poorly, but upon passage, adapted variants arise that grow >100 times better. We have sequenced the entire domain encoding the E2, 6K, and E1 proteins of a number of these adapted variants and found that most acquired two amino acid changes, which had cumulative effects. In three independent passage series, amino acid 380 of E2, which is in the transmembrane domain, was mutated from the original isoleucine to serine in two instances and to valine once. We have now changed this residue to seven others by site-directed mutagenesis and tested the effects of these mutations on the growth of both the chimera [SIN(RRE1)] and of parental Sindbis. These results indicate that the transmembrane domains of glycoproteins E2 and E1 of alphaviruses interact in a sequence-dependent manner and that this interaction is required for efficient budding and assembly of infectious virions.
Strauss
Ellen G
EG
Division of Biology 156-29, California Institute of Technology, Pasadena, CA 91125, USA. strausse@cco.caltech.edu
Lenches
Edith M
EM
Strauss
James H
JH
D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001483:Base Sequence; D002213:Capsid / Q000235:genetics / Q000502:physiology; D036022:Capsid Proteins; D002460:Cell Line; D006224:Cricetinae; D004279:DNA, Viral; D014644:Genetic Variation; D057927:Hydrophobic and Hydrophilic Interactions; D007532:Isoleucine / Q000235:genetics / Q000502:physiology; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000502:physiology; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D012398:Ross River virus / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012845:Sindbis Virus / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D014759:Viral Envelope Proteins / Q000235:genetics* / Q000502:physiology; D019065:Virus Assembly
C092026:6K protein, Sindbis virus; D036022:Capsid Proteins; D004279:DNA, Viral; C110266:E1 protein, Ross River virus; C085817:E2 protein, Ross River virus; D008562:Membrane Glycoproteins; D014759:Viral Envelope Proteins; C022012:glycoprotein E1, Sindbis virus; C064950:glycoprotein E2, Sindbis virus; D007532:Isoleucine