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dc.contributor.authorLasek-Nesselquist, Erica  Concept link
dc.contributor.authorWisecaver, Jennifer H.  Concept link
dc.contributor.authorHackett, Jeremiah D.  Concept link
dc.contributor.authorJohnson, Matthew D.  Concept link
dc.identifier.citationBMC Genomics 16 (2015): 805en_US
dc.description© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in BMC Genomics 16 (2015): 805, doi:10.1186/s12864-015-2052-9.en_US
dc.description.abstractOrganelle retention is a form of mixotrophy that allows organisms to reap metabolic benefits similar to those of photoautotrophs through capture of algal prey and sequestration of their plastids. Mesodinium rubrum is an abundant and broadly distributed photosynthetic marine ciliate that steals organelles from cryptophyte algae, such as Geminigera cryophila. M. rubrum is unique from most other acquired phototrophs because it also steals a functional nucleus that facilitates genetic control of sequestered plastids and other organelles. We analyzed changes in G. cryophila nuclear gene expression and transcript abundance after its incorporation into the cellular architecture of M. rubrum as an initial step towards understanding this complex system. We compared Illumina-generated transcriptomes of the cryptophyte Geminigera cryophila as a free-living cell and as a sequestered nucleus in M. rubrum to identify changes in protein abundance and gene expression. After KEGG annotation, proteins were clustered by functional categories, which were evaluated for over- or under-representation in the sequestered nucleus. Similarly, coding sequences were grouped by KEGG categories/pathways, which were then evaluated for over- or under-expression via read count strategies. At the time of sampling, the global transcriptome of M. rubrum was dominated (~58–62 %) by transcription from its stolen nucleus. A comparison of transcriptomes from free-living G. cryophila cells to those of the sequestered nucleus revealed a decrease in gene expression and transcript abundance for most functional protein categories within the ciliate. However, genes coding for proteins involved in photosynthesis, oxidative stress reduction, and several other metabolic pathways revealed striking exceptions to this general decline. Major changes in G. cryophila transcript expression after sequestration by M. rubrum and the ciliate’s success as a photoautotroph imply some level of control or gene regulation by the ciliate and at the very least reflect a degree of coordination between host and foreign organelles. Intriguingly, cryptophyte genes involved in protein transport are significantly under-expressed in M. rubrum, implicating a role for the ciliate’s endomembrane system in targeting cryptophyte proteins to plastid complexes. Collectively, this initial portrait of an acquired transcriptome within a dynamic and ecologically successful ciliate highlights the remarkable cellular and metabolic chimerism of this system.en_US
dc.description.sponsorshipThe authors wish to acknowledge the support of NSF award 1354773.en_US
dc.publisherBioMed Centralen_US
dc.rightsAttribution 4.0 International*
dc.subjectMesodinium rubrumen_US
dc.subjectGeminigera cryophilaen_US
dc.subjectAcquired phototrophyen_US
dc.subjectDifferential gene expressionen_US
dc.subjectChimeric metabolismen_US
dc.subjectOrganelle retentionen_US
dc.titleInsights into transcriptional changes that accompany organelle sequestration from the stolen nucleus of Mesodinium rubrumen_US

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Attribution 4.0 International
Except where otherwise noted, this item's license is described as Attribution 4.0 International