Hong Y, Coussens P M
Department of Animal Science, Michigan State University, East Lansing 48824.
J Virol. 1994 Jun;68(6):3593-603. doi: 10.1128/JVI.68.6.3593-3603.1994.
Marek's disease virus (MDV) is an oncogenic avian herpesvirus whose genomic structure is similar to those of herpes simplex virus and varicella-zoster virus. Repeat regions of the MDV genome have been intensively investigated because of a potential relationship to MDV oncogenicity and abundant expression of immediate-early transcripts. In this study, a 1.6-kb immediate-early transcript was localized to the BamHI-I2 region by Northern (RNA) hybridization analysis. With cDNA cloning and sequencing, two cDNAs of 1.4 kb (C1) and 1.35 kb (C2) were identified. Both cDNAs are derived from spliced mRNAs spanning the BamHI-H and -I2 fragments. C1 and C2 use the same splice acceptors and 3' ends, but they differ at their 5' ends and utilize different splice donors. The upstream promoter-enhancer region of C1 cDNA has been defined as a bidirectional regulatory region shared by the MDV pp38 gene. Sequencing analysis shows two small open reading frames (ORFs) within each cDNA (ORF1a and ORF2 in C1, ORF1b and ORF2 in C2). Potential ORFs of the sequence have no significant homology with any known protein in the Swiss-Protein data base. DNA fragments encoding ORF1a and ORF1b were cloned into pGEX-3X vectors to produce glutathione S-transferase fusion proteins and induce antisera. In Western blot (immunoblot) analysis of MDV-infected-cell lysates, a 14-kDa polypeptide was identified by antisera against both ORF1a and ORF1b. This 14-kDa protein is expressed in cells which are lytically infected with MDV strains GA, Md11 passage 14 (oncogenic), and Md11 passage 83 (attenuated), as well as in the latently MDV-infected and transformed MSB-1 cell line.
马立克氏病病毒（MDV）是一种致癌性禽疱疹病毒，其基因组结构与单纯疱疹病毒和水痘 - 带状疱疹病毒相似。由于MDV基因组的重复区域与MDV致癌性以及立即早期转录本的大量表达可能存在关联，因此对其进行了深入研究。在本研究中，通过Northern（RNA）杂交分析将一个1.6 kb的立即早期转录本定位到BamHI - I2区域。通过cDNA克隆和测序，鉴定出了两个分别为1.4 kb（C1）和1.35 kb（C2）的cDNA。这两个cDNA均来自跨越BamHI - H和 - I2片段的剪接mRNA。C1和C2使用相同的剪接受体和3'末端，但它们的5'末端不同且使用不同的剪接供体。C1 cDNA的上游启动子 - 增强子区域已被定义为MDV pp38基因共享的双向调控区域。测序分析显示每个cDNA内有两个小开放阅读框（ORF）（C1中的ORF1a和ORF2，C2中的ORF1b和ORF2）。该序列的潜在ORF与瑞士蛋白质数据库中的任何已知蛋白质均无显著同源性。将编码ORF1a和ORF1b的DNA片段克隆到pGEX - 3X载体中以产生谷胱甘肽S - 转移酶融合蛋白并诱导抗血清。在对MDV感染细胞裂解物的蛋白质印迹（免疫印迹）分析中，针对ORF1a和ORF1b的抗血清鉴定出了一种14 kDa的多肽。这种14 kDa的蛋白质在被MDV毒株GA、Md11传代14（致癌性）和Md11传代83（减毒）裂解感染的细胞中表达，也在潜伏感染MDV并转化的MSB - 1细胞系中表达。
