title: Genomic structure and RNA polymerase activity in Leishmania virus.
abstract: 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.
authors.affiliation: Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts.
authors.forename: G
authors.initials: G
authors.lastname: Widmer
authors.forename: J L
authors.initials: JL
authors.lastname: Patterson
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D002499:Centrifugation, Density Gradient; D002586:Cesium; D002712:Chlorides; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004587:Electrophoresis, Agar Gel; D007892:Leishmania braziliensis / Q000382:microbiology*; D012328:RNA Viruses / Q000201:enzymology / Q000235:genetics*; D012330:RNA, Double-Stranded / Q000096:biosynthesis; D012367:RNA, Viral / Q000096:biosynthesis*; D013395:Sucrose; D014771:Virion / Q000201:enzymology / Q000235:genetics
chemical_list: D002712:Chlorides; D012330:RNA, Double-Stranded; D012367:RNA, Viral; D002586:Cesium; D013395:Sucrose; D012321:DNA-Directed RNA Polymerases; C028019:cesium chloride