A Novel Bunyavirus-Like Virus of Trypanosomatid Protist Parasites.
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ABSTRACT:
SUBMITTER: Akopyants NS
PROVIDER: S-EPMC4974306 | biostudies-literature | 2016 Aug
REPOSITORIES: biostudies-literature
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A Novel Bunyavirus-Like Virus of Trypanosomatid Protist Parasites.
Akopyants Natalia S NS Lye Lon-Fye LF Dobson Deborah E DE Lukeš Julius J Beverley Stephen M SM
Genome announcements 20160804 4
We report here the sequences for all three segments of a novel RNA virus (LepmorLBV1) from the insect trypanosomatid parasite Leptomonas moramango This virus belongs to a newly discovered group of bunyavirus-like elements termed Leishbunyaviruses (LBV), the first discovered from protists related to arboviruses infecting humans. ...[more]
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Project description:BackgroundLarge amino acid transporter gene families were identified from the genome sequences of three parasitic protists, Trypanosoma brucei, Trypanosoma cruzi and Leishmania major. These genes encode molecular sensors of the external host environment for trypanosomatid cells and are crucial to modulation of gene expression as the parasite passes through different life stages. This study provides a comprehensive phylogenetic account of the origins of these genes, redefining each locus according to a positional criterion, through the integration of phyletic identity with comparative gene order information.ResultsEach locus was individually specified by its surrounding gene order and associated with homologs showing the same position ('homoeologs') in other species, where available. Bayesian and maximum likelihood phylogenies were in general agreement on systematic relationships and confirmed several 'orthology sets' of genes retained since divergence from the common ancestor. Reconciliation analysis quantified the scale of duplication and gene loss, as well as identifying further apparent orthology sets, which lacked conservation of genomic position. These instances suggested substantial genomic restructuring or transposition. Other analyses identified clear instances of evolutionary rate changes post-duplication, the effects of concerted evolution within tandem gene arrays and gene conversion events between syntenic loci.ConclusionDespite their importance to cell function and parasite development, the repertoires of AAT loci in trypanosomatid parasites are relatively fluid in both complement and gene dosage. Some loci are ubiquitous and, after an ancient origin through transposition, originated through descent from the ancestral trypanosomatid. However, reconciliation analysis demonstrated that unilateral expansions of gene number through tandem gene duplication, transposition of gene duplicates to otherwise well conserved genomic positions, and differential patterns of gene loss have produced largely customised and idiosyncratic AAT repertoires in all three species. Not least in T. brucei, which seems to have retained fewer ancestral loci and has acquired novel loci through a complex mix of tandem and transpositive duplication.
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