Small RNAs reveal two target sites of the RNA-maturation factor Mbb1 in the chloroplast of Chlamydomonas

Article Article scientifique Article Small RNAs reveal two target sites of the RNA-maturation factor Mbb1 in the chloroplast of Chlamydomonas eng 2014 author Loizeau Karen 733851 author Qu Yujiao author Depp Sébastien 527676 author Fiechter Vincent 502636 author Ruwe Hannes author Legendre Lefebvre Linnka 134661 author Schmitz-Linneweber Christian author Goldschmidt-Clermont Michel P. 25594 3286-3297 10.1093/nar/gkt1272 24335082 0305-1048 Many chloroplast transcripts are protected against exonucleolytic degradation by RNA-binding proteins. Such interactions can lead to the accumulation of short RNAs (sRNAs) that represent footprints of the protein partner. By mining existing data sets of Chlamydomonas reinhardtii small RNAs, we identify chloroplast sRNAs. Two of these correspond to the 5'-ends of the mature psbB and psbH messenger RNAs (mRNAs), which are both stabilized by the nucleus-encoded protein Mbb1, a member of the tetratricopeptide repeat family. Accordingly, we find that the two sRNAs are absent from the mbb1 mutant. Using chloroplast transformation and site-directed mutagenesis to survey the psbB 5' UTR, we identify a cis-acting element that is essential for mRNA accumulation. This sequence is also found in the 5' UTR of psbH, where it plays a role in RNA processing. The two sRNAs are centered on these cis-acting elements. Furthermore, RNA binding assays in vitro show that Mbb1 associates with the two elements specifically. Taken together, our data identify a conserved cis-acting element at the extremity of the psbH and psbB 5' UTRs that plays a role in the processing and stability of the respective mRNAs through interactions with the tetratricopeptide repeat protein Mbb1 and leads to the accumulation of protected sRNAs. 5' Untranslated Regions Base Sequence Chlamydomonas reinhardtii/genetics/metabolism Chloroplast Proteins/metabolism Chloroplasts/genetics/metabolism Molecular Sequence Data Mutation Photosystem II Protein Complex/genetics/metabolism Protein Biosynthesis RNA Processing Post-Transcriptional RNA Stability RNA Chloroplast/chemistry/metabolism Messenger/metabolism Small Untranslated/chemistry/metabolism RNA-Binding Proteins/metabolism Regulatory Sequences Ribonucleic Acid Dewey 570 Dewey 580 Swiss National Science Foundation Chloroplast Signaling 133089 CH Project funding European Commission Towards a better sunlight to biomass conversion efficiency in microalgae 245070 SUNBIOPATH EU FP7 43 Département de biologie moléculaire 161 45 Département des sciences végétales 163 false 833 Groupe Goldschmidt-Clermont Nucleic acids research 42 5 7a5ce4f6-df64-46c6-8a22-8ee27589f6ca Article (Published version) Public Loizeau_NAR_revised.pdf 1338851 application/pdf openAccess Faculté des sciences / Section de biologie / Département de biologie moléculaire Faculté des sciences / Section de biologie / Département des sciences végétales

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Small RNAs reveal two target sites of the RNA-maturation factor Mbb1 in the chloroplast of Chlamydomonas	Nucleic acids research			2014	626	211

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Loizeau, Karen