Project description:The roles of RNA-binding proteins as chaperones in the lifecycles of mRNAs are not well understood. The mammalian mitochondrial genome has been compressed over evolution to a size of just 16 kb, nevertheless the expression of its genes requires transcription, RNA processing, translation and RNA decay, much like the more complex chromosomal systems, providing an opportunity to use it as a model system to understand the fundamental aspects of gene expression. Here we combine RNase footprinting with PAR-CLIP at unprecedented depth to reveal the importance of RNA-protein interactions guided by the LRPPRC/SLIRP complex in dictating RNA folding within the mitochondrial transcriptome. We show that LRPPRC, in complex with its protein partner SLIRP, binds throughout the mitochondrial transcriptome, with a preference for mRNAs, and its loss affects the entire secondary structure and stability of the transcriptome. We demonstrate that the LRPPRC/SLIRP complex is a global RNA chaperone that stabilizes RNA structures to expose the required sites for translation, stabilization and polyadenylation. Our findings reveal a general mechanism where extensive RNA-protein interactions ensure that RNA is accessible for its biological functions.
Project description:The roles of RNA-binding proteins as chaperones in the lifecycles of mRNAs are not well understood. The mammalian mitochondrial genome has been compressed over evolution to a size of just 16 kb, nevertheless the expression of its genes requires transcription, RNA processing, translation and RNA decay, much like the more complex chromosomal systems, providing an opportunity to use it as a model system to understand the fundamental aspects of gene expression. Here we combine RNase footprinting with PAR-CLIP at unprecedented depth to reveal the importance of RNA-protein interactions guided by the LRPPRC/SLIRP complex in dictating RNA folding within the mitochondrial transcriptome. We show that LRPPRC, in complex with its protein partner SLIRP, binds throughout the mitochondrial transcriptome, with a preference for mRNAs, and its loss affects the entire secondary structure and stability of the transcriptome. We demonstrate that the LRPPRC/SLIRP complex is a global RNA chaperone that stabilizes RNA structures to expose the required sites for translation, stabilization and polyadenylation. Our findings reveal a general mechanism where extensive RNA-protein interactions ensure that RNA is accessible for its biological functions.
Project description:The roles of RNA-binding proteins as chaperones in the lifecycles of mRNAs are not well understood. The mammalian mitochondrial genome has been compressed over evolution to a size of just 16 kb, nevertheless the expression of its genes requires transcription, RNA processing, translation and RNA decay, much like the more complex chromosomal systems, providing an opportunity to use it as a model system to understand the fundamental aspects of gene expression. Here we combine RNase footprinting with PAR-CLIP at unprecedented depth to reveal the importance of RNA-protein interactions guided by the LRPPRC/SLIRP complex in dictating RNA folding within the mitochondrial transcriptome. We show that LRPPRC, in complex with its protein partner SLIRP, binds throughout the mitochondrial transcriptome, with a preference for mRNAs, and its loss affects the entire secondary structure and stability of the transcriptome. We demonstrate that the LRPPRC/SLIRP complex is a global RNA chaperone that stabilizes RNA structures to expose the required sites for translation, stabilization and polyadenylation. Our findings reveal a general mechanism where extensive RNA-protein interactions ensure that RNA is accessible for its biological functions.
Project description:The roles of RNA-binding proteins as chaperones in the lifecycles of mRNAs are not well understood. The mammalian mitochondrial genome has been compressed over evolution to a size of just 16 kb, nevertheless the expression of its genes requires transcription, RNA processing, translation and RNA decay, much like the more complex chromosomal systems, providing an opportunity to use it as a model system to understand the fundamental aspects of gene expression. Here we combine RNase footprinting with PAR-CLIP at unprecedented depth to reveal the importance of RNA-protein interactions guided by the LRPPRC/SLIRP complex in dictating RNA folding within the mitochondrial transcriptome. We show that LRPPRC, in complex with its protein partner SLIRP, binds throughout the mitochondrial transcriptome, with a preference for mRNAs, and its loss affects the entire secondary structure and stability of the transcriptome. We demonstrate that the LRPPRC/SLIRP complex is a global RNA chaperone that stabilizes RNA structures to expose the required sites for translation, stabilization and polyadenylation. Our findings reveal a general mechanism where extensive RNA-protein interactions ensure that RNA is accessible for its biological functions.
Project description:The mammalian mitochondrial genome encodes thirteen proteins of the oxidative phosphorylation system, crucial in aerobic energy transduction. These proteins are translated from 9 monocistronic and 2 bicistronic transcripts, whose native structures remain unexplored, leaving fundamental molecular determinants of mitochondrial gene expression unknown. To address this knowledge gap, we developed a mitoDMS-MaPseq approach and used DREEM clustering to resolve the native mt-mRNA structurome in human mitochondria. In this way, we gained insights into mt-mRNA biology and translation regulatory mechanisms, including a unique translational frameshifting for the ATP8/ATP6 transcript. Furthermore, absence of the mt-mRNA maintenance factor LRPPRC led to a mitochondrial transcriptome structured differently, with specific mRNA regions exhibiting increased or decreased structuredness. This highlights the role of LRPPRC in maintaining mRNA folding to promote mt-mRNA stabilization and efficient translation. In conclusion, our mt-mRNA folding maps reveal novel mitochondrial gene expression mechanisms, serving as a detailed reference and tool for studying them in different physiological and pathological contexts.