Identification and analyses of glycoprotein B of human herpesvirus 7.
The gene for the human herpes virus 7 (HHV-7) glycoprotein B (gB) has been identified by sequencing a molecularly cloned HHV-7 DNA fragment. A 2.5-kb open reading frame (ORF) encoded a protein of 822 amino acids with characteristics of a transmembrane glycoprotein, and showed the strongest similarity (56.5%) with the human herpesvirus 6 (HHV-6) gB. The genes for the transport/capsid assembly protein (tp/cap) and the DNA polymerase (pol) existed upstream and downstream of the gB gene, respectively. This arrangement was the same as that of HHV-6. Antisera were generated by immunizing mice with a glutathione S-transferase-carboxy terminal gB fusion protein. Immunofluorescent tests demonstrated that the antisera reacted specifically with HHV-7 antigens in cytoplasm of infected cells. The antisera immunoprecipitated proteins with apparent molecular masses of 51, 63 and 112 kDa from HHV-7 infected cells by pulse-chase analysis. In the presence of tunicamycin, the protein with a molecular mass of 112 kDa was replaced by a protein with a molecular mass of 88 kDa, and this size was consistent with the predicted size of the primary translation product of the HHV-7 gB gene. These results suggested that the protein with a molecular mass of 112 kDa was a glycoprotein synthesized by addition of N-linked oligosaccharides to a non-glycosylated precursor of the protein with a molecular mass of 88 kDa and then cleaved into the proteins with molecular masses of 51 and 63 kDa in HHV-7 infected cells.
Hata
A
A
Department of Virology, Osaka University, Japan.
Mukai
T
T
Isegawa
Y
Y
Yamanishi
K
K
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D016199:Herpesvirus 7, Human / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011498:Protein Precursors / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*
D011498:Protein Precursors; D014759:Viral Envelope Proteins; C105061:glycoprotein B, human herpesvirus 7