Perng G C, Slanina S M, Ghiasi H, Nesburn A B, Wechsler S L
Ophthalmology Research Laboratories, Cedars-Sinai Medical Center Research Institute, Los Angeles, California 90048, USA.
J Virol. 1996 Mar;70(3):2014-8. doi: 10.1128/JVI.70.3.2014-2018.1996.
The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) gene is essential for efficient spontaneous reactivation of HSV-1 from latency. However, neither the mechanism by which LAT carries out this function nor the region of LAT responsible for this function in known. LAT is transcribed as an unstable 8.3-kb RNA that gives rise to a very stable 2-kb LAT RNA that is readily detected in latently infected sensory neurons. We show here that 371 of the 662 nucleotides located between the start of LAT transcription and the 5' end of the 2-kb LAT RNA do not appear to be essential for wild-type levels of spontaneous reactivation in the rabbit ocular model of HSV-1 latency. We deleted LAT nucleotides 76 to 447 from both copies of the LAT gene (one in each viral long repeat) to produce the mutant dLAT371. Rabbits were ocularly infected with dLAT371, and spontaneous reactivation was measured in comparison with the marker-rescued virus dLAT371R. Both dLAT371 and dLAT371R had spontaneous reactivation rates of approximately 13 to 14%. This was consistent with the parental McKrae wild-type virus (11.7%; P = 0.49) and significantly higher than the LAT transcription-negative mutant dLAT2903 (2.4%; P < 0.0001). Southern analysis confirmed that the spontaneously reactivated dLAT371 virus retained the deletion in both copies of LAT. Therefore, it appeared that the function of LAT involved in efficient spontaneous reactivation mapped outside the 371-nucleotide region deleted from the LAT gene of dLAT371.
单纯疱疹病毒1型（HSV-1）潜伏相关转录物（LAT）基因对于HSV-1从潜伏状态高效自发再激活至关重要。然而，LAT执行此功能的机制以及负责此功能的LAT区域均不为人所知。LAT转录生成一种不稳定的8.3 kb RNA，进而产生一种非常稳定的2 kb LAT RNA，后者在潜伏感染的感觉神经元中易于检测到。我们在此表明，在HSV-1潜伏的兔眼模型中，位于LAT转录起始点与2 kb LAT RNA的5'端之间的662个核苷酸中的371个核苷酸，对于野生型水平的自发再激活似乎并非必不可少。我们从LAT基因的两个拷贝（每个病毒长重复序列中各一个）中删除了LAT核苷酸76至447，以产生突变体dLAT371。用dLAT371对兔进行眼内感染，并与标记拯救病毒dLAT371R比较测量自发再激活情况。dLAT371和dLAT371R的自发再激活率均约为13%至14%。这与亲本McKrae野生型病毒一致（11.7%；P = 0.49），且显著高于LAT转录阴性突变体dLAT2903（2.4%；P < 0.0001）。Southern分析证实，自发再激活的dLAT371病毒在LAT的两个拷贝中均保留了缺失。因此，似乎参与高效自发再激活的LAT功能定位于从dLAT371的LAT基因中删除的371个核苷酸区域之外。
