Membrane fusion activity, oligomerization, and assembly of the rabies virus glycoprotein.
The spike glycoprotein (G protein) of rabies virus (CVS strain) expressed in HeLa cells from cloned cDNA mediated membrane fusion after exposure to pHs of 6.1 or below. Chemical crosslinking showed that the rabies G protein, like the vesicular stomatitis virus (VSV) G protein, could be crosslinked to dimers and trimers, indicating that rabies G protein is a trimer. However, unlike the VSV G protein, rabies G protein trimers were not stable to sedimentation in sucrose gradients, even at a mildly acidic pH which stabilizes the VSV G protein trimers. In addition, we report that the expressed rabies virus G protein was functional because it could assemble into VSV particles (tsO45) lacking VSV G protein and rescue infectivity. These VSV (rabies) pseudotypes were neutralized only by an antibody to the rabies G protein. We also examined the properties of a hybrid protein containing the extracellular domain of the rabies virus glycoprotein and the transmembrane and cytoplasmic domains of the VSV G protein. This protein was transported to the cell surface and could be crosslinked to form dimers and trimers, but had little or no detectable membrane fusion activity. The lack of fusion activity was paradoxical because the hybrid protein could rescue VSV infectivity, although the titers were lower than those obtained with the wild-type rabies G protein.
Whitt
M A
MA
Department of Pathology, Yale University School of Medicine, New Haven, Connecticut 06510.
Buonocore
L
L
Prehaud
C
C
Rose
J K
JK
D000818:Animals; D000956:Antigens, Viral; D001483:Base Sequence; D002460:Cell Line / Q000382:microbiology; D002499:Centrifugation, Density Gradient; D006224:Cricetinae; D005434:Flow Cytometry; D005816:Genetic Complementation Test; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D046911:Macromolecular Substances; D008561:Membrane Fusion; D008562:Membrane Glycoproteins; D051379:Mice; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D011820:Rabies virus / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014721:Vesicular stomatitis Indiana virus / Q000235:genetics / Q000378:metabolism*; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014760:Viral Fusion Proteins / Q000737:chemistry / Q000378:metabolism*
D000956:Antigens, Viral; C028391:G protein, vesicular stomatitis virus; D006023:Glycoproteins; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins; D011993:Recombinant Fusion Proteins; D014759:Viral Envelope Proteins; D014760:Viral Fusion Proteins; C064951:glycoprotein G, Rabies virus