In-depth functional characterization of chloroplast-localized mTERF proteins
Final Report Abstract
Organellar gene expression (OGE) is crucial for proper development of plants and their acclimation to environmental changes, but how OGE is regulated is only partially understood. OGE requires various nucleus-encoded proteins that promote transcription, splicing, trimming and editing of organellar RNAs, and regulate their translation. Members of the so-called “mitochondrial transcription termination factor” (mTERF) family are found in metazoans and plants and regulate OGE at different levels. Until now the molecular functions of only six of the 35 Arabidopsis thaliana mTERF proteins have been investigated in more detail. After we had identified mTERF6 as a factor promoting chloroplast trnI.2 maturation we sought to understand the molecular function of mTERF6 in more detail. Furthermore, we aimed at revealing the functions of not investigated putative chloroplast-localized mTERF proteins. However, because rumors reached us with respect to other groups working on mTERF6, we decided to focus on mTERF10, -11 and -12 which we previously assigned to the “chloroplastassociated” group, and mTERF2 and mTERF27, whose homologs had been identified in maize nucleoids. We could show that all members of the chloroplast-associated group are localized to nucleoids. Moreover, mTERF10 mTERF11 and mTERF27, but not mTERF12, are involved in the response to salt tolerance. Additionally, we found mTERF27 to be localised to mitochondria (and not nucleoids), whereas mTERF2 is indeed localised to nucleoids. Because mterf2 knock-out mutant plants are embryo lethal, artificial microRNA lines were generated to study the biological roles(s) of mTERF2 in seedlings and adult plants. In the mterf2 knock-down mutant plants, photosynthesis and growth are impaired, and flowering is delayed. We identified RNA targets of mTERF2 with the help of RIP-Seq and showed by using RNA-Seq, Northern-blot and real-time analyses that this protein is required for splicing of the group IIB introns of ycf3 (intron 1) and rps12.
Publications
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(2017) Organellar gene expression and acclimation of plants to environmental stress. Front Plant Sci 8: 387
Leister D, Wang L, Kleine T
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(2017). Arabidopsis thaliana mTERF10 and mTERF11, but not mTERF12, are involved in the response to salt stress. Front Plant Sci 8: 1213
Xu D, Leister D, Kleine T
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(2020) Cellulose defects in the Arabidopsis secondary cell wall promote early chloroplast development. Plant J 101: 156-170
Xu D, Dhiman R, Garibay A, Mock HP, Leister D, Kleine T
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(2020). Extending the repertoire of mTERF proteins with functions in organellar gene expression. Mol Plant 13: 817-819
Leister D, Kleine T
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(2021). Arabidopsis mitochondrial transcription termination factor mTERF2 promotes splicing of group IIB introns. Cells 10: 315
Lee K, Leister D, Kleine T
