Leishmania RNA virus 1-mediated cap-independent translation.
Leishmania RNA virus 1-mediated cap-independent translation.
复制标题
利什曼原虫 RNA 病毒 1 介导的帽独立翻译。
DOI：
10.1128/mcb.15.9.4884
复制
发表时间：
1995
影响因子：
5.3
通讯作者：
LeBowitz,JH
中科院分区：
文献类型：
--
作者：
Maga,JA;Widmer,G;LeBowitz,JH
Recently, a group of relatedLeishmaniaRNA viruses (LeishmaniaRNA virus 1 [LRV1]) has been isolated fromLeishmania guyanensisandL. brasiliensis. These viruses persist in the cytoplasm and contain double-stranded RNA genomes. Miniexon sequences are absent from the 5′ end of the viral RNA, and the 5′ end of the viral RNA lacks a cap structure, suggesting that LRV1 has evolved a cap-independent mechanism of translation. Cap-independent translation of picornavirus genomic RNA requires aciselement, within the 5′ untranslated region (UTR), referred to as an internal ribosome entry site (IRES). In order to find out if the 5′ UTR of LRV1 possessed IRES activity, we modified aLeishmaniaexpression vector, pX63NEO-GUS, so that it would produce a dicistronic transcript in which the neomycin phosphotransferase gene was separated from the downstream β-glucuronidase (GUS) gene by the LRV1 5′ UTR. High levels of GUS activity were detected inL. majorstably transformed with this plasmid. Elimination of the first 120 nucleotides of the viral 5′ UTR lowered GUS activity 10-fold. Furthermore, when the entire 5′ UTR was eliminated, GUS activity was undetectable. These results, together with the absence oftrans-spliced GUS transcripts, are consistent with the hypothesis that the 5′ UTR of LRV1 functions as an IRES element. The ability to couple expression of genes via an IRES element should prove useful in genetic experiments withLeishmaniaspp.
