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

摘要

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.