A phylogenetic mosaic plastid proteome and unusual plastid-targeting signals in the green-colored dinoflagellate Lepidodinium chlorophorum

BMC Evolutionary Biology

Research Article

Yuji Inagaki¹  Marianne A Minge²  Ole K Tørresen²  Kjetill S Jakobsen³  Kiyotaka Takishita⁴  Dag Klaveness⁵  Kamran Shalchian-Tabrizi⁵  Ian Probert⁶ 

[1] Center for Computational Sciences, Institute for Biological Sciences, University of Tsukuba, 305-8577, Tsukuba, Ibaraki, Japan;Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, N-0316, Oslo, Norway;Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, N-0316, Oslo, Norway;Microbial Evolutionary Research Group (MERG), Department of Biology, University of Oslo, N-0316, Oslo, Norway;Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 237-0061, Yokosuka, Kanagawa, Japan;Microbial Evolutionary Research Group (MERG), Department of Biology, University of Oslo, N-0316, Oslo, Norway;Roscoff Culture Collection (RCC), Station Biologique de Roscoff, Place Georges Teissier, 29682, Roscoff, France;

关键词: Transit Peptide;    RuBisCO Activase;    Secondary Plastid;    Primary Plastid;    Endosymbiotic Gene Transfer;   

DOI  :  10.1186/1471-2148-10-191

 received in 2009-12-13, accepted in 2010-06-21,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundPlastid replacements through secondary endosymbioses include massive transfer of genes from the endosymbiont to the host nucleus and require a new targeting system to enable transport of the plastid-targeted proteins across 3-4 plastid membranes. The dinoflagellates are the only eukaryotic lineage that has been shown to have undergone several plastid replacement events, and this group is thus highly relevant for studying the processes involved in plastid evolution. In this study, we analyzed the phylogenetic origin and N-terminal extensions of plastid-targeted proteins from Lepidodinium chlorophorum, a member of the only dinoflagellate genus that harbors a green secondary plastid rather than the red algal-derived, peridinin-containing plastid usually found in photosynthetic dinoflagellates.ResultsWe sequenced 4,746 randomly picked clones from a L. chlorophorum cDNA library. 22 of the assembled genes were identified as genes encoding proteins functioning in plastids. Some of these were of green algal origin. This confirms that genes have been transferred from the plastid to the host nucleus of L. chlorophorum and indicates that the plastid is fully integrated as an organelle in the host. Other nuclear-encoded plastid-targeted protein genes, however, are clearly not of green algal origin, but have been derived from a number of different algal groups, including dinoflagellates, streptophytes, heterokonts, and red algae. The characteristics of N-terminal plastid-targeting peptides of all of these genes are substantially different from those found in peridinin-containing dinoflagellates and green algae.ConclusionsL. chlorophorum expresses plastid-targeted proteins with a range of different origins, which probably arose through endosymbiotic gene transfer (EGT) and horizontal gene transfer (HGT). The N-terminal extension of the genes is different from the extensions found in green alga and other dinoflagellates (peridinin- and haptophyte plastids). These modifications have likely enabled the mosaic proteome of L. chlorophorum.

【 授权许可】

Unknown   
© Minge et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.