Jackson M K, Knowles D P, Stem T A, Harwood W G, Robinson M M, Cheevers W P
Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164.
Virology. 1991 Jan;180(1):389-94. doi: 10.1016/0042-6822(91)90044-c.
The nucleotide sequence of the pol-env intergenic region of two isolates of caprine arthritis-encephalitis virus (CAEV) was determined. Two open reading frames (orfs) were identified, designated Q and S by homology with visna virus. CAEV orf S is a single exon encoding a deduced 87-amino acid gene product sharing 36 amino acid identities with the visna trans-acting transcriptional activator (Tat). Ten of these identities comprise a conserved CGCRLCNPGW sequence similar to a cysteine-rich domain essential for trans-activation by human immunodeficiency virus Tat. To determine if transcription promoted by the CAEV long terminal repeat (LTR) could be stimulated in CAEV-infected goat synovial membrane cells, a plasmid (pCAE-CAT) expressing bacterial chloramphenicol acetyltransferase (CAT) under control of the CAEV LTR was transfected into uninfected and infected cells. Sixfold enhancement of CAT activity was observed in infected cells using 100 ng of transfected plasmid. To determine if the pol-env region encodes a gene product which trans-activates the CAEV LTR, goat synovial membrane cells were cotransfected with pCAE-CAT and pRSV-1.9, a plasmid expressing the pol-env region under control of the Rous sarcoma virus LTR. Results indicated that the CAEV genome encodes a tat gene product attributable to orf S.
测定了两株山羊关节炎-脑炎病毒（CAEV）pol-env基因间隔区的核苷酸序列。鉴定出两个开放阅读框（ORF），根据与维斯纳病毒的同源性分别命名为Q和S。CAEV的ORF S是一个单外显子，编码一个推导的87个氨基酸的基因产物，与维斯纳反式作用转录激活因子（Tat）有36个氨基酸相同。其中10个相同氨基酸构成一个保守的CGCRLCNPGW序列，类似于人免疫缺陷病毒Tat反式激活所必需的富含半胱氨酸结构域。为了确定在感染CAEV的山羊滑膜细胞中CAEV长末端重复序列（LTR）所促进的转录是否能被刺激，将在CAEV LTR控制下表达细菌氯霉素乙酰转移酶（CAT）的质粒（pCAE-CAT）转染到未感染和感染的细胞中。使用100 ng转染质粒时，在感染细胞中观察到CAT活性增强了6倍。为了确定pol-env区域是否编码一个能反式激活CAEV LTR的基因产物，将山羊滑膜细胞与pCAE-CAT和pRSV-1.9共转染，pRSV-1.9是一个在劳斯肉瘤病毒LTR控制下表达pol-env区域的质粒。结果表明，CAEV基因组编码一个归因于ORF S的tat基因产物。
