Yoshida S, Lee L F, Yanagida N, Nazerian K
USDA-Agricultural Research Service, Avian Disease and Oncology Laboratory, East Lansing, Michigan 48823.
Virology. 1994 May 1;200(2):484-93. doi: 10.1006/viro.1994.1211.
The nucleotide sequences of the glycoprotein B (gB) genes of Marek's disease virus (MDV) serotypes 2 and 3 were determined (gB-2 and gB-3, respectively). The genomic locations of these genes coincide with that of the gB gene of serotype 1 MDV (gB-1). Alignment with gB-1 (Ross et al., 1989, J. Gen. Virol. 70, 1789-1804) revealed predicted amino acid identities of 83 and 82% for gB-2 and gB-3, respectively. Excluding the predicted N-terminal signal sequences, 8 of 9 potential N-linked glycosylation sites and all 10 cysteine residues in gB-1 are conserved in both gB-2 and gB-3. In addition, the putative proteolytic cleavage sites for processing of precursors (gp100s) to gp60s and gp49s are conserved among the three gB homologs. Fowlpox virus (FPV) recombinants expressing either the gB-2 or the gB-3 gene were constructed. We detected expression of authentic gB-2 and gB-3 complexes in cells infected with these FPV recombinants. Digestion of immunoprecipitated gB-1 and gB-3 with endoglycosidases revealed that both gp60s are modified by the additions of O-glycans and complex carbohydrates after cleavage of gp100s, while gp100s and gp49s contain only high-mannose carbohydrates. We confirm that the size differences between gB-1 and gB-3 complexes are due to different carbohydrate modifications.
测定了2型和3型马立克氏病病毒（MDV）糖蛋白B（gB）基因的核苷酸序列（分别为gB-2和gB-3）。这些基因的基因组位置与1型MDV的gB基因（gB-1）一致。与gB-1比对（Ross等人，1989年，《普通病毒学杂志》70卷，1789 - 1804页）显示，gB-2和gB-3预测的氨基酸同一性分别为83%和82%。排除预测的N端信号序列后，gB-1中9个潜在的N-糖基化位点中的8个以及所有10个半胱氨酸残基在gB-2和gB-3中均保守。此外，三种gB同源物中用于将前体（gp100s）加工成gp60s和gp49s的假定蛋白水解切割位点是保守的。构建了表达gB-2或gB-3基因的禽痘病毒（FPV）重组体。我们在感染这些FPV重组体的细胞中检测到了真实的gB-2和gB-3复合物的表达。用内切糖苷酶消化免疫沉淀的gB-१和gB-३，结果显示，在gp१००s切割后，两种gp६०s都通过添加O-聚糖和复合碳水化合物进行了修饰，而gp१००s和gp४९s仅含有高甘露糖碳水化合物。我们证实gB-१和gB-३复合物之间的大小差异是由于不同碳水化合物修饰所致。
