Linkage of an alphavirus host-range restriction to the carbohydrate-processing phenotypes of the host cell.
The Sindbis virus mutant NE2G216 retains PE2 in place of E2 in its virion structure. NE2G216 is a host-range mutant that replicates with near-normal kinetics in vertebrate cells, but displays severely restricted growth in cultured mosquito cells (C6/36) due to defects in the virus maturation process. In this study we tested the hypothesis that the host-range phenotype of NE2G216 was linked to the differences in carbohydrate-processing phenotypes between vertebrate and arthropod cells. Arthropod cell-derived glycoproteins are distinguishable from those synthesized in vertebrate cells by the absence of complex- and hybrid-type N-linked oligosaccharides. To test our hypothesis we compared the growth of the wild-type virus, TRSB, NE2G216 and three PE2-containing, C6/36 cell-adapted variants, in vertebrate cells treated with 1-deoxymannojirimycin (1-dMM). 1-dMM inhibits the Golgi alpha-mannosidase I enzyme and limits oligosaccharide processing to high-mannose forms (Man(8-9)GlcNAc(2)). The growth of TRSB was not restricted by the action of 1-dMM; however, NE2G216 was restricted in a dose-dependent manner. In contrast, the growth of each PE2-containing, C6/36 cell-adapted mutant was enhanced by low concentrations of 1-dMM (up to 1500%) and was only slightly affected by the higher concentrations. These results demonstrate that virion maturation functions of NE2G216 are sensitive to the structure of cis-linked oligosaccharides, and indicate that the carbohydrate-processing phenotypes of the host cell can influence viral host-range and function as a selective pressure in alphavirus evolution.
Boehme
K W
KW
Division of Life Sciences, University of Texas at San Antonio, 6900 North Loop 1604 West, San Antonio, TX 78249-0662, USA.
Williams
J C
JC
Johnston
R E
RE
Heidner
H W
HW
D017485:1-Deoxynojirimycin / Q000494:pharmacology; D000330:Aedes / Q000166:cytology / Q000821:virology; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology; D016466:CHO Cells; D002460:Cell Line; D006224:Cricetinae; D003588:Cytopathogenic Effect, Viral; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006031:Glycosylation; D008361:Mannosidases / Q000037:antagonists & inhibitors; D009154:Mutation; D009844:Oligosaccharides / Q000378:metabolism*; D012845:Sindbis Virus / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism* / Q000472:pathogenicity; D014461:Ultracentrifugation; D014771:Virion / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity
D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D009844:Oligosaccharides; D017485:1-Deoxynojirimycin; D008361:Mannosidases