Salmon B, Baines J D
Department of Microbiology and Immunology, Cornell University, Ithaca, New York 14853, USA.
J Virol. 1998 Apr;72(4):3045-50. doi: 10.1128/JVI.72.4.3045-3050.1998.
The U(L)15 gene of herpes simplex virus (HSV) is one of several genes required for the packaging of viral DNA into intranuclear B capsids to produce C capsids that become enveloped at the inner nuclear membrane. A rabbit antiserum directed against U(L)15-encoded protein recognized three proteins with apparent Mrs of 79,000, 80,000, and 83,000 in highly purified B capsids. The 83,000-Mr protein was detected in type C capsids and comigrated with the product of a U(L)15 cDNA transcribed and translated in vitro. The 83,000- and 80,000-Mr proteins were readily detected in purified virions. Inasmuch as (i) none of these proteins were detectable in capsids purified from cells infected with HSV-1(deltaU(L)15), a virus lacking an intact U(L)15 gene, and (ii) corresponding proteins in capsids purified from cells infected with a recombinant virus [HSV-1(R7244), containing a 20-codon tag at the 3' end of U(L)15] were decreased in electrophoretic mobility relative to the wild-type proteins, we conclude that the proteins with apparent Mrs of 83,000, 80,000, and 79,000 are products of U(L)15 with identical C termini. The 79,000-, 80,000-, and 83,000-Mr proteins remained associated with B capsids in the presence of 0.5 M guanidine HCl and remained detectable in capsids treated with 2.0 M guanidine HCl and lacking proteins associated with the capsid core. These data, therefore, indicate that U(L)15-encoded proteins are integral components of B capsids. Only the 83,000-Mr protein was detected in B capsids purified from cells infected with viruses lacking the U(L)6, U(L)17, or U(L)28 genes, which are required for DNA cleavage and packaging, suggesting that capsid association of the 80,000- and 79,000-Mr proteins requires intact cleavage and packaging machinery. These data, therefore, indicate that capsid association of the 80,000- and 79,000-Mr U(L)15-encoded proteins reflects a previously unrecognized step in the DNA cleavage and packaging reaction.
单纯疱疹病毒（HSV）的U(L)15基因是将病毒DNA包装到核内B衣壳中以产生C衣壳（C衣壳在内核膜处被包膜）所需的几个基因之一。一种针对U(L)15编码蛋白的兔抗血清在高度纯化的B衣壳中识别出三种表观分子量分别为79,000、80,000和83,000的蛋白。在C型衣壳中检测到了83,000分子量的蛋白，并且它与体外转录和翻译的U(L)15 cDNA产物迁移率相同。在纯化的病毒粒子中很容易检测到83,000和80,000分子量的蛋白。鉴于（i）从感染了HSV-1(deltaU(L)15)（一种缺乏完整U(L)15基因的病毒）的细胞中纯化的衣壳中检测不到这些蛋白中的任何一种，以及（ii）从感染了重组病毒[HSV-1(R7244)，在U(L)15的3'端含有一个20密码子标签]的细胞中纯化的衣壳中的相应蛋白相对于野生型蛋白在电泳迁移率上降低，我们得出结论，表观分子量为83,000、80,000和79,000的蛋白是具有相同C末端的U(L)15产物。在0.5 M盐酸胍存在的情况下，79,000、80,000和83,000分子量的蛋白仍与B衣壳结合，并且在用2.0 M盐酸胍处理且缺乏与衣壳核心相关蛋白的衣壳中仍可检测到。因此，这些数据表明U(L)15编码的蛋白是B衣壳的组成成分。仅在从感染了缺乏DNA切割和包装所需的U(L)6、U(L)17或U(L)28基因的病毒的细胞中纯化的B衣壳中检测到了83,000分子量的蛋白，这表明80,000和79,000分子量的蛋白与衣壳的结合需要完整的切割和包装机制。因此，这些数据表明80,000和79,000分子量的U(L)15编码蛋白与衣壳的结合反映了DNA切割和包装反应中一个以前未被认识到的步骤。
