Avian endogenous retrovirus EAV-HP shares regions of identity with avian leukosis virus subgroup j and the avian retrotransposon ART-CH
Avian endogenous retrovirus EAV-HP shares regions of identity with avian leukosis virus subgroup j and the avian retrotransposon ART-CH
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DOI：
10.1128/jvi.74.3.1296-1306.2000
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发表时间：
2000-02-01
影响因子：
5.4
通讯作者：
Venugopal, K
中科院分区：
文献类型：
--
作者：
Sacco, MA;Flannery, DMJ;Venugopal, K
据报道，鸡基因组中存在一种新的内源性逆转录病毒元件，称为EAV-HP，序列与禽白血病病毒（ALV） J亚群的环境基因非常接近（L.M. Smith, it A. Toye，等）。豪斯,电视。李建军，李建军，李建军，等。中国生物医学工程学报，第8期：391 - 398页，1999)。为了确定这些逆转录病毒基因的基因组结构，我们分别从N系鸡基因组DNA酵母人工染色体文库和肉鸡21系lambda文库中测定了两个EAV-HP原病毒克隆的完整序列，结果表明，这两个克隆的EAV-HP序列具有98%的同源性和典型的原病毒结构。两个EAV-HP克隆显示了相同的大缺失，包括部分gag，整个pol和部分air基因。EAV-HP克隆的env区与HPRS-103的env序列有97%的一致性，HPRS-103是jalv原型亚群。EAV-HP的5‘区包括长末端重复序列（LTR）的R和U5区，未翻译的先导区，以及假定的Sag区的5’端与禽类反转录转座子序列的97%相同。ART-CH。剩下的插科打诨！与其他ALV序列的同源性不到60%。LTR的U3区域与其他逆转录病毒不同，但包含一些作为启动子功能所需的保守基序。为了检验这种内源性逆转录病毒LTR作为转录启动子的能力，我们在荧光素酶报告基因试验中比较了EAV-HP和HPRS-103 LTR U3区域R。EAV-HP LTR U3构建体检测到低荧光素酶活性。在接近缺乏启动子或增强子元件的中心载体中观察到的水平，表明这些元件作为弱启动子起作用，可能解释了它们在鸡胚胎中的低表达水平。
The existence of novel endogenous retrovirus elements in the chicken genome, designated EAV-HP, with close sequence identity to the env gene of avian leukosis virus (ALV) subgroup J has been reported (L.M. Smith, it A. Toye, ii. Howes, TV. Bumstead, L. N. Payne, and K. Venugopal, J, Gen, Virol. 80:261-268, 1999). To resolve the genome structure of these retroviral elements, we have determined the complete sequence of two proviral clones of EAV-HP from a Line N chicken genomic DNA yeast artificial chromosome library and from a meat-type chicken line 21 lambda library, The EAV-HP sequences from the two lines were 98% identical and had a typical provirus structure. The two EAV-HP clones showed identical large deletions spanning part of the gag, the entire pol, and part of the air genes. The env region of the EAV-HP clones was 97% identical to the env sequence of HPRS-103, the prototype subgroup J ALV. The 5' region of EAV-HP comprising the R and U5 regions of the long terminal repeat (LTR), the untranslated leader, and the 5' end of the putative Sag region were 97% identical to the avian retrotransposon sequence? ART-CH. The remaining gag sequence! shared less than 60% identity with other ALV sequences. The U3 region of the LTR was distinct from those of other retroviruses but contained some of the conserved motifs required for functioning as a promoter. To examine the ability of this endogenous retroviral LTR to function as a transcriptional promoter, the EAV-HP and HPRS-103 LTR U3 regions R ere compared in a luciferase reporter gene assay. The low luciferase activity detected with the EAV-HP LTR U3 constructs. at levels close to those observed for a central vector lacking the promoter or enhancer elements, suggested that these elements function as a weak promoter, possibly accounting for their low expression levels in chicken embryos.