Li D S, Pastorek J, Zelník V, Smith G D, Ross L J
AFRC Institute for Animal Health, Compton Laboratory, Newbury, Berkshire, U.K.
J Gen Virol. 1994 Jul;75 ( Pt 7):1713-22. doi: 10.1099/0022-1317-75-7-1713.
Libraries of cDNA were generated from polyadenylated RNAs derived from Marek's disease virus (MDV)-transformed cell lines by directional cloning of oligo-(dT)-primed cDNAs in lambda gt22A. Analysis of the libraries for viral sequences showed that a number of cDNA clones originated from transcripts mapping in the BamHI A region of the MDV genome. Sequencing and fine mapping of these cDNAs suggested that the RNA transcripts expressed from this region were either in the sense or antisense direction with respect to the MDV homologue of the ICP4 gene of herpes simplex virus. The longest cDNA clone from antisense transcripts was 2756 bp long and partially overlapped the 5' end of the coding region of the ICP4 gene. The cDNA clone contained at least four introns, shown by comparison of its sequence with the sequence of the ICP4 gene. The presence of introns was confirmed by PCR analysis. All the introns have the consensus splice donor and acceptor signals at their 5' and 3' ends respectively. Northern blot analysis showed that the ICP4 gene homologue of MDV was abundantly transcribed only in lytically infected fibroblasts, whereas transcripts complementary to the ICP4 gene were the major transcripts in MDV-transformed cell lines and lymphomas. The transcripts complementary to ICP4 consist of two major RNA species approximately 15 kb and 1.32 kb long. The results suggest that there might be an inverse relationship between the abundance of ICP4 transcripts and their complementary transcripts in MDV-infected and transformed cells.
通过将寡聚（dT）引发的cDNA定向克隆到λgt22A中，从马立克氏病病毒（MDV）转化的细胞系衍生的聚腺苷酸化RNA中生成cDNA文库。对文库中的病毒序列进行分析表明，许多cDNA克隆源自定位在MDV基因组BamHI A区域的转录本。对这些cDNA进行测序和精细定位表明，从该区域表达的RNA转录本相对于单纯疱疹病毒ICP4基因的MDV同源物而言，要么是正义方向，要么是反义方向。来自反义转录本的最长cDNA克隆长2756 bp，部分与ICP4基因编码区的5'端重叠。通过将其序列与ICP4基因的序列进行比较，发现该cDNA克隆至少包含四个内含子。通过PCR分析证实了内含子的存在。所有内含子在其5'和3'端分别具有共有剪接供体和受体信号。Northern印迹分析表明，MDV的ICP4基因同源物仅在裂解感染的成纤维细胞中大量转录，而与ICP4基因互补的转录本是MDV转化的细胞系和淋巴瘤中的主要转录本。与ICP4互补的转录本由两种主要的RNA种类组成，长度约为15 kb和1.32 kb。结果表明，在MDV感染和转化的细胞中，ICP4转录本及其互补转录本的丰度之间可能存在反比关系。
