Molecular Cloning and Sequencing of a Specific cDNA Mapping to the Bam HI-I2 and -LFragments within the Inverted Repeats of Unique Long Region(IRL) from the Genom e of the Marek′s Disease Herpesvirus (MDV) Oncogenic Strain Beijing-1

Isolation and identification of a specific cDNA mapping to the BamHI I2 and L fragments from the inverted repeats of unique long region(IRL) in the genome of Marek′s disease herpesvirus (MDV) oncogenic strain Beijing 1 had been previously performed by us. In this study, the specific cDNA was cloned into phagemid vectors PUC118 and 119 on the basis of prefabricated two recognized sites in synthesized primers. Recombinants were further identified with restriction pattern, molecular hybridization, and DNA sequencing analysis. It was demonstrated that this cDNA with 720 base pair (bp) contained sequences including a potentially incomplete open reading frame (ORF) encoded a 238 amino acids (aa) predicted polypeptide which was significantly homologous not only to part of N terminus of meq, but also to that of XbaI ClaI subfragment of BamHI L. In accordance with these data, following results could be deduced:①the 720 bp cDNA represented a spliced transcript;②meq transcription could be extended from the right hand end of BamHI I2 to the adjacent BamHI L fragment;③the L region was transcribed in varying degrees\ in MDV induced lymphoblastoid tumors.

马立克病疱疹病毒致瘤株基因组IRL区Bam H I I2和L片段内一特异性cDNA的分离与鉴定

目的 了解马立克病疱疹病毒（ＭＤＶ）强毒ＧＡ株Ｂａｍ ＨＩＬ片段在ＭＤＶ致瘤毒株京－１株（中国特有的地方株）所诱导的淋巴肿瘤组织中转录状况。方法 从人工感染ＭＤＶ致瘤株京－１株发病鸡内脏淋巴肿瘤组织中分离ｍ ＲＮＡ，根据已发表的ＭＤＶ肿瘤候选基因ｍ ｅｑ 基因序列和我们已测定的强毒ＧＡ株Ｂａｍ ＨＩＬ片段序列，设计两段寡核苷酸引物，以此ｍ ＲＮＡ为模板经逆转录合成ｃＤＮＡ，应用ＰＣＲ法进行目的基因扩增。用非放射性Ｄｉｇｏｘｉｇｅｎｉｎ 分别标记ＧＡ株基因组Ｂａｍ ＨＩＩ２和ＬＤＮＡ片段，制成核酸探针，分别与ＰＣＲ产物作Ｓｏｕｔｈｅｒｎ ｂｌｏｔ分子杂交鉴定。结果 逆转录聚合酶链反应（ＲＴ－ＰＣＲ）扩增的ｃＤＮＡ大小约７３０ ｂｐ，该ｃＤＮＡ能同时与上述两探针发生免疫呈色反应。结论 ①ＭＤＶ ｍ ｅｑ基因的转录可以延伸到其右侧的Ｂａｍ ＨＩＬ片段区；②Ｂａｍ ＨＩＬ区在ＭＤＶ致瘤株京－１株所诱导的淋巴肿瘤组织中可发生转录。

基因探针技术检测血清1型马立克氏病病毒的研究

选用马立克氏病病毒（MDV）GA株BamHI基因文库中LDNA片段，制成DIG—标记的MDV核酸探针，分别对1型MDV强毒株（BJ-1株）和弱毒株（Md11／75c株）感染材料的核酸进行dotblot杂交检测，结果显示均有阳性呈色反应；而对MDV血清2型（SB-1株）、3型（Fe126株）及禽网状内皮组织增殖病病毒（REV）和淋巴细胞性白血病病毒（LLV）感染细胞的核酸，作上述同样检测，则均未见任何颜色显现。