Human herpesvirus 8 glycoprotein B (gB), gH, and gL can mediate cell fusion.
Herpesvirus entry into cells and herpesvirus-induced cell fusion are related processes in that virus penetration proceeds by fusion of the viral envelope and cell membrane. To characterize the human herpesvirus 8 (HHV-8) glycoproteins that can mediate cell fusion, a luciferase reporter gene activation assay was used. Chinese hamster ovary (CHO) cells expressing the HHV-8 glycoproteins of interest along with a luciferase reporter gene under the control of the T7 promoter were cocultivated with human cells transfected with T7 RNA polymerase. Because HHV-8 glycoprotein B (gB) expressed in CHO cells localizes to the perinuclear region, a truncated form of gB (designated gB(MUT)) that lacks putative endocytosis signals was constructed by deletion of the distal 58 amino acids of the cytoplasmic tail. HHV-8 gB(MUT) was expressed efficiently on the surface of CHO cells. HHV-8 gB, gH, and gL could mediate the fusion of CHO cells with two different human cell types, embryonic kidney cells and B lymphocytes. Substituting gB(MUT) for gB significantly enhanced the fusion of CHO cells with human embryonic kidney cells but not B lymphocytes. Thus, two human cell types known to be susceptible to HHV-8 entry were also suitable targets for cell fusion induced by HHV-8 gB, gH, and gL. For human embryonic kidney cells and B cells at least, optimal fusion was noted with the expression of all three HHV-8 glycoproteins.
Pertel
Peter E
PE
Division of Infectious Diseases, Northwestern University Medical School, Chicago, Illinois, USA. p-pertel@northwestern.edu
D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes; D016466:CHO Cells; D002460:Cell Line; D006224:Cricetinae; D019288:Herpesvirus 8, Human / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D006801:Humans; D008561:Membrane Fusion; D008969:Molecular Sequence Data; D014162:Transfection; D014759:Viral Envelope Proteins / Q000235:genetics* / Q000378:metabolism*
D014759:Viral Envelope Proteins; C116207:glycoprotein B, human herpesvirus 8; C077407:glycoprotein L, Human herpesvirus 1