Jang H K, Ono M, Kim T J, Izumiya Y, Damiani A M, Matsumura T, Niikura M, Kai C, Mikami T
Department of Veterinary Microbiology, Faculty of Agriculture, The University of Tokyo, Japan.
Virus Res. 1998 Nov;58(1-2):137-47. doi: 10.1016/s0168-1702(98)00110-5.
Studies on the Marek's disease virus (MDV) serotype 2 (MDV2) genome may be important for understanding the naturally nononcogenic nature of the virus. To determine the complete DNA sequence of MDV2 unique short (Us) region, genomic BamHI fragments F, M1 and R were sequenced. The MDV2 Us region is 12109 bp long and contains 12 potential open reading frames (ORFs) likely to encode for proteins. Seven of them exhibit homologies to herpes simplex virus type 1 (HSV-1) US1 (ICP22), US2, US3 (protein kinase), US6 (gD), US7 (gI), US8 (gE) and US10 genes. These ORFs are conserved in a similar arrangement with those of HSV-1, except for US10 which is transposed in the Us regions of all three MDV serotypes. The predicted amino acid sequence of MDV2 ORF6 is homologous to SORF3 of the other serotypes of MDV serotype 1 (MDV1) and herpesvirus of turkeys (HVT) and to infectious laryngotracheitis virus SR1. In addition, four ORFs, which have been identified around the Us and inverted repeat junction regions, have no apparent relation to any other known herpesvirus genes. The identified ORFs in the MDV2 Us region were more colinear with their previously reported locations of MDV1 than with those of HVT and other alphaherpesviruses. Ten of the 12 ORFs in the MDV2 Us region were expressed and transcribed with 3'-coterminal transcripts and/or a unique transcript in the virus-infected cells. Compared to other MDV serotypes, the MDV2 Us-encoded proteins showed 46-70% and 33-59% identities with equivalent of MDV1 and HVT at the amino acid level, respectively. Our present data will be useful to understand the different pathogenicity among serotypes of MDV and to allow precise manipulation of the genes for a possible use in genetically engineered vaccines.
对马立克氏病病毒2型（MDV2）基因组的研究对于理解该病毒天然的非致瘤特性可能具有重要意义。为了确定MDV2独特短片段（Us）区域的完整DNA序列，对基因组BamHI片段F、M1和R进行了测序。MDV2的Us区域长12109 bp，包含12个可能编码蛋白质的潜在开放阅读框（ORF）。其中7个与单纯疱疹病毒1型（HSV-1）的US1（ICP22）、US2、US3（蛋白激酶）、US6（gD）、US7（gI）、US8（gE）和US10基因具有同源性。这些ORF与HSV-1的ORF以相似的排列方式保守存在，但US10在所有三种MDV血清型的Us区域中发生了移位。MDV2 ORF6的预测氨基酸序列与MDV1血清型的其他血清型以及火鸡疱疹病毒（HVT）的SORF3和传染性喉气管炎病毒SR1同源。此外，在Us和反向重复连接区域周围鉴定出的4个ORF与任何其他已知的疱疹病毒基因没有明显关系。MDV2 Us区域中鉴定出的ORF与其先前报道的MDV1位置相比，比与HVT和其他α疱疹病毒的位置更共线。MDV2 Us区域中的12个ORF中有10个在病毒感染细胞中通过3'共末端转录本和/或独特转录本进行表达和转录。与其他MDV血清型相比，MDV-2 Us编码的蛋白质在氨基酸水平上与MDV1和HVT的等效物分别具有46-70%和33-59%的同一性。我们目前的数据将有助于理解MDV血清型之间的不同致病性，并允许对基因进行精确操作，以便可能用于基因工程疫苗。
