On the complexity of chloroplast RNA metabolism: psaA trans-splicing can be bypassed in chlamydomonas

Article Article scientifique Article On the complexity of chloroplast RNA metabolism: psaA trans-splicing can be bypassed in chlamydomonas eng 2014 author Legendre Lefebvre Linnka 134661 author Merendino Livia 520450 author Rivier Cristian Pablo 86553 author Goldschmidt-Clermont Michel P. 25594 2697-2707 10.1093/molbev/msu215 25053803 0737-4038 In the chloroplast, the posttranscriptional steps of gene expression are remarkably complex. RNA maturation and translation rely on a large cohort of nucleus-encoded proteins that act specifically on a single target transcript or a small set of targets. For example in the chloroplast of Chlamydomonas, trans-splicing of the two split introns of psaA requires at least 14 nucleus-encoded proteins. To investigate the functional significance of this complex trans-splicing pathway, we have introduced an intron-less copy of psaA in the chloroplast genomes of three mutants deficient in trans-splicing and of the wild type. We find that the intron-less psaA gene rescues the mutant phenotypes. The growth of strains with the intron-less psaA is indistinguishable from the wild type under the set of different experimental conditions that were investigated. Thus, the trans-splicing factors do not appear to have any other essential function and trans-splicing of psaA can be bypassed. We discuss how these observations support the hypothesis that complex RNA metabolism in the chloroplast may in part be the result of a nonadaptive evolutionary ratchet. Genetic drift may lead to the accumulation of chloroplast mutations and the recruitment of compensatory nuclear suppressors from large preexisting pools of genes encoding RNA-binding proteins. Chloroplast RNA processing Splicing constructive neutral evolution Chlamydomonas Synthetic biology Dewey 580 Dewey 570 Swiss National Science Foundation Chloroplast signaling and acclimation to changing light 146300 CH Project funding Swiss National Science Foundation Biogenesis and regulation of the photosynthetic apparatus 117712 CH Projects 43 Département de biologie moléculaire 161 45 Département des sciences végétales 163 false 833 Groupe Goldschmidt-Clermont Molecular biology and evolution 31 10 63a7bdc0-bd3b-467c-996c-2c1d8fae0036 Article (Accepted version) Restricted Lefebvre-Legendre_MolBiolEv_revised.pdf 1374238 application/pdf restrictedAccess Faculté des sciences / Section de biologie / Département de biologie moléculaire Faculté des sciences / Section de biologie / Département des sciences végétales

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On the complexity of chloroplast RNA metabolism: psaA trans-splicing can be bypassed in chlamydomonas	Molecular biology and evolution			2014	695	0

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Rivier, Cristian Pablo