Comparative life cycle transcriptomics revises Leishmania mexicana genome annotation and links a chromosome duplication with parasitism of vertebrates

Fiebig, M., Kelly, S. and Gluenz, E. (2015) Comparative life cycle transcriptomics revises Leishmania mexicana genome annotation and links a chromosome duplication with parasitism of vertebrates. PLoS Pathogens, 11(10), e1005186. (doi: 10.1371/journal.ppat.1005186)

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Leishmania spp. are protozoan parasites that have two principal life cycle stages: the motile promastigote forms that live in the alimentary tract of the sandfly and the amastigote forms, which are adapted to survive and replicate in the harsh conditions of the phagolysosome of mammalian macrophages. Here, we used Illumina sequencing of poly-A selected RNA to characterise and compare the transcriptomes of L. mexicana promastigotes, axenic amastigotes and intracellular amastigotes. These data allowed the production of the first transcriptome evidence-based annotation of gene models for this species, including genome-wide mapping of trans-splice sites and poly-A addition sites. The revised genome annotation encompassed 9,169 protein-coding genes including 936 novel genes as well as modifications to previously existing gene models. Comparative analysis of gene expression across promastigote and amastigote forms revealed that 3,832 genes are differentially expressed between promastigotes and intracellular amastigotes. A large proportion of genes that were downregulated during differentiation to amastigotes were associated with the function of the motile flagellum. In contrast, those genes that were upregulated included cell surface proteins, transporters, peptidases and many uncharacterized genes, including 293 of the 936 novel genes. Genome-wide distribution analysis of the differentially expressed genes revealed that the tetraploid chromosome 30 is highly enriched for genes that were upregulated in amastigotes, providing the first evidence of a link between this whole chromosome duplication event and adaptation to the vertebrate host in this group. Peptide evidence for 42 proteins encoded by novel transcripts supports the idea of an as yet uncharacterised set of small proteins in Leishmania spp. with possible implications for host-pathogen interactions.

Item Type:Articles
Additional Information:Funding: MF was supported by a Wellcome Trust (studentship (092870/Z/10/Z). SK was supported by a Leverhulme Trust Early Career Fellowship and the Queen’s College Oxford. EG is a Royal Society University Research Fellow.
Glasgow Author(s) Enlighten ID:Gluenz, Dr Eva
Authors: Fiebig, M., Kelly, S., and Gluenz, E.
College/School:College of Medical Veterinary and Life Sciences > School of Infection & Immunity
Journal Name:PLoS Pathogens
Publisher:Public Library of Science
ISSN (Online):1553-7374
Published Online:09 October 2015
Copyright Holders:Copyright © 2015 Fiebig et al. T
First Published:First published in PLoS Pathogens 11(10):e1005186
Publisher Policy:Reproduced under a Creative Commons license

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