Spivack J G, Woods G M, Fraser N W
Wistar Institute, Philadelphia, Pennsylvania 19104.
J Virol. 1991 Dec;65(12):6800-10. doi: 10.1128/JVI.65.12.6800-6810.1991.
Herpes simplex virus type 1 establishes latent infection in trigeminal ganglia of mice infected via the eye. A family of three colinear viral transcripts (LATs), 2.0, 1.5, and 1.45 kb, is present in latently infected ganglia. To characterize these LATs, lambda gt10 cDNA libraries were constructed with RNAs isolated from the trigeminal ganglia of latently infected mice. A series of recombinant bacteriophage were isolated containing cDNA inserts covering 1.7 kb of the 2.0-kb LAT. Splice junctions of the smaller LATs and the 3' end of the 2.0-kb LAT were identified by sequence analysis of RNA polymerase chain reaction products. No splice acceptor site, which does not support the hypotheses that the 2.0-kb LAT is an intron. However, the data are consistent with the possibility of a short leader sequence or multiple LAT transcription start sites. To generate the smaller 1.5- and 1.45-kb LATs, there is a 559-nucleotide intron spliced from the 2.0-kb LAT in strain F and a 556-nucleotide intron in strain 17+. The nucleotide sequences at the 5' and 3' ends of these introns are characteristic of spliced transcripts from eukaryotic protein-encoding genes, with one significant difference; i.e., the 5' end of the LAT intron is GC instead of the consensus sequence GT. This splice donor sequence is conserved in herpes simplex virus type 1 strains F, 17+, and KOS. Processing of the 2.0-kb LAT to form the spliced LATs preserves two open reading frames (ORFs) at the 3' end of the LATs; no new ORFs are created. Splicing of the LATs positions a 276-nucleotide leader sequence close to these ORFs and removes an intron that inhibits their translation in vitro. The novel 5' structure of the intron within the 2.0-kb LAT may be part of a control mechanism for transcription processing that results in splicing of the LATs only in sensory neurons during latent infection and reactivation but not during the viral replication cycle.
单纯疱疹病毒1型通过眼部感染小鼠后，会在三叉神经节中建立潜伏感染。在潜伏感染的神经节中存在一个由三个共线性病毒转录本（LATs）组成的家族，分别为2.0、1.5和1.45 kb。为了对这些LATs进行表征，用从潜伏感染小鼠的三叉神经节中分离的RNA构建了λgt10 cDNA文库。分离出一系列重组噬菌体，其cDNA插入片段覆盖了2.0 kb LAT的1.7 kb。通过对RNA聚合酶链反应产物的序列分析，确定了较小LATs的剪接位点以及2.0 kb LAT的3'末端。未发现剪接受体位点，这与2.0 kb LAT是一个内含子的假设不符。然而，这些数据与存在短前导序列或多个LAT转录起始位点的可能性是一致的。为了产生较小的1.5和1.45 kb LATs，在F株中，从2.0 kb LAT剪接出一个559个核苷酸的内含子，在17 +株中剪接出一个556个核苷酸的内含子。这些内含子5'和3'末端的核苷酸序列具有真核生物蛋白质编码基因剪接转录本的特征，但有一个显著差异，即LAT内含子的5'末端是GC而不是共有序列GT。这种剪接供体序列在单纯疱疹病毒1型F株、17 +株和KOS株中是保守的。2.0 kb LAT加工形成剪接后的LATs时，在LATs的3'末端保留了两个开放阅读框（ORFs）；没有产生新的ORFs。LATs的剪接将一个276个核苷酸的前导序列定位在这些ORFs附近，并去除了一个在体外抑制其翻译的内含子。2.0 kb LAT内内含子的新型5'结构可能是转录加工控制机制的一部分，该机制导致LATs仅在潜伏感染和再激活期间的感觉神经元中剪接，而在病毒复制周期中不剪接。
