Widmer G, Patterson J L
Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts.
J Virol. 1991 Aug;65(8):4211-5. doi: 10.1128/JVI.65.8.4211-4215.1991.
Viral particles infecting some stocks of the protozoan parasite Leishmania braziliensis subsp. guyanensis contain a double-stranded RNA genome of ca. 5 kbp and are associated with an RNA-dependent RNA polymerase which synthesizes in vitro double-stranded and single-stranded, genome-length transcripts. The majority of viral transcripts are single-stranded and templated from one genomic strand. The putative replicase generates double-stranded RNA by synthesizing the opposite strand on a preexisting RNA template. These data are compatible with a replicative cycle proposed for the yeast viruses. Purification of the Leishmania virus on CsCl yields virus without double-strand synthesis activity, while this activity is consistently present in unpurified virus and in particles from sucrose gradients. The deficiency in double-strand synthesis in CsCl-derived virions correlates with the accessibility of the viral polymerase and genomic RNA to exogenously added enzymes, indicative of a structural modification of the viral capsid.
感染原生动物寄生虫巴西利什曼原虫圭亚那亚种某些毒株的病毒粒子含有一个约5千碱基对的双链RNA基因组，并与一种RNA依赖的RNA聚合酶相关联，该聚合酶在体外合成双链和单链的基因组长度转录本。大多数病毒转录本是单链的，以一条基因组链为模板。假定的复制酶通过在预先存在的RNA模板上合成互补链来产生双链RNA。这些数据与为酵母病毒提出的复制周期相一致。在氯化铯上纯化利什曼病毒得到的病毒没有双链合成活性，而这种活性在未纯化的病毒和蔗糖梯度中的病毒粒子中始终存在。氯化铯衍生的病毒粒子中双链合成的缺陷与病毒聚合酶和基因组RNA对外源添加酶的可及性相关，表明病毒衣壳发生了结构修饰。
