title: Phylogeny, integration and expression of sigma virus-like genes in Drosophila.
abstract: The recent and surprising discovery of widespread NIRVs (non-retroviral integrated RNA viruses) has highlighted the importance of genomic interactions between non-retroviral RNA viruses and their eukaryotic hosts. Among the viruses with integrated representatives are the rhabdoviruses, a family of negative sense single-stranded RNA viruses. We identify sigma virus-like NIRVs of Drosophila spp. that represent unique cases where NIRVs are closely related to exogenous RNA viruses in a model host organism. We have used a combination of bioinformatics and laboratory methods to explore the evolution and expression of sigma virus-like NIRVs in Drosophila. Recent integrations in Drosophila provide a promising experimental system to study functionality of NIRVs. Moreover, the genomic architecture of recent NIRVs provides an unusual evolutionary window on the integration mechanism. For example, we found that a sigma virus-like polymerase associated protein (P) gene appears to have been integrated by template switching of the blastopia-like LTR retrotransposon. The sigma virus P-like NIRV is present in multiple retroelement fused open reading frames on the X and 3R chromosomes of Drosophila yakuba - the X-linked copy is transcribed to produce an RNA product in adult flies. We present the first account of sigma virus-like NIRVs and the first example of NIRV expression in a model animal system, and therefore provide a platform for further study of the possible functions of NIRVs in animal hosts.
authors: Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA. ballinge@buffalo.edu
authors: Matthew J
authors: MJ
authors: Ballinger
authors: Jeremy A
authors: JA
authors: Bruenn
authors: Derek J
authors: DJ
authors: Taylor
mesh_terms: D000818:Animals; D019295:Computational Biology; D004330:Drosophila / Q000235:genetics* / Q000821:virology; D005814:Genes, Viral; D049750:Genome, Insect; D016013:Likelihood Functions; D010802:Phylogeny; D018626:Retroelements; D012209:Rhabdoviridae / Q000235:genetics*; D017423:Sequence Analysis, RNA; D016662:Virus Integration
chemical_list: D018626:Retroelements