A functional twintron, “zombie” twintrons and a hypermobile group II intron invading itself in plant mitochondria
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PROVIDER: PRJEB34500 | ENA |
REPOSITORIES: ENA
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Project description:The occurrence of group II introns in plant mitochondrial genomes is strikingly different between the six major land plant clades, contrasting their highly conserved counterparts in chloroplast DNA. Their present distribution likely reflects numerous ancient intron gains and losses during early plant evolution before the emergence of seed plants. As a novelty for plant organelles, we here report on five cases of twintrons, introns-within-introns, in the mitogenomes of lycophytes and hornworts. An internal group II intron interrupts an intron-borne maturase of an atp9 intron in Lycopodiaceae, whose splicing precedes splicing of the external intron. An invasive, hypermobile group II intron in cox1, has conquered nine further locations including a previously overlooked sdh3 intron and, most surprisingly, also itself. In those cases, splicing of the external introns does not depend on splicing of the internal introns. Similar cases are identified in the mtDNAs of hornworts. Although disrupting a group I intron-encoded protein in one case, we could not detect splicing of the internal group II intron in this 'mixed' group I/II twintron. We suggest the name 'zombie' twintrons (half-dead, half-alive) for such cases where splicing of external introns does not depend any more on prior splicing of fossilized internal introns.
| S-EPMC7049729 | biostudies-literature
Project description:Introns are universally present in the nuclear genomes of eukaryotes. The budding yeast, an otherwise intron-poor species, preserves two sets of ribosomal protein (RP) genes differing primarily in their introns. Despite recent findings on the role of RP introns under stress and starvation, understanding the contribution of introns to ribosome regulation remains challenging. Here, combining isogrowth profiling with single-cell protein measurements, we found that introns can mediate inducible phenotypic heterogeneity conferring a clear fitness advantage. Osmotic stress leads to bimodal expression of the small ribosomal subunit protein Rps22B, mediated by an intron in the 5′ untranslated region of its transcript. The two resulting yeast subpopulations differ in their ability to cope with starvation. Low Rps22B protein levels resulted in prolonged survival under sustained starvation, while high Rps22B levels enabled cells to grow faster after transient starvation. Further, yeast growing at high sugar concentrations – similar to those in ripe grapes – exhibit bimodal Rps22B expression when approaching stationary phase. Differential intron-mediated regulation of RP genes thus provides a way to diversify the population when starvation looms in natural environments. Our findings reveal a new role for introns in inducing phenotypic heterogeneity in changing environments and suggest that duplicated RP genes in yeast contribute to resolving the evolutionary conflict between precise expression control and environmental responsiveness.
2022-02-23 | GSE197174 | GEO
Project description:Single nucleotide variants (SNVs) in intronic regions have yet to be systematically investigated for their disease-causing potential. Using known pathogenic and neutral intronic SNVs (iSNVs) as training data, we develop the RegSNPs-intron algorithm based on a random forest classifier that integrates RNA splicing, protein structure and evolutionary conservation features. RegSNPs-intron shows excellent performance in evaluating the pathogenic impacts of iSNVs. Using a high-throughput functional reporter assay called ASSET-seq (ASsay for Splicing using ExonTrap and sequencing), we evaluate the impact of regSNPs-intron predictions on splicing outcome. Together, RegSNPs-intron and ASSET-seq enable effective prioritization of iSNVs for disease pathogenesis.
2019-09-30 | GSE138130 | GEO
Project description:camelus dromedarius mitochondria
| PRJEB63970 | ENA
Project description:Intron evolution in Saccharomycetaceae
| PRJNA253808 | ENA
Project description:Recent studies have demonstrated that mitochondria can be transferred between different cell types to control metabolic homeostasis. However, whether the mitochondria transfer network occurred in the skeletal system or regulate skeletal metabolic homeostasis in vivo is not fully elucidated. Herein, we found that osteolineage cells transfer mitochondria to CD11b+ myeloid, B220+ lymphoid and hematopoietic stem and progenitor cells (HSPCs), of which monocytes/macrophages received the most transferred mitochondria. This process was inhibited by GC treatment contributing to the progression of glucocorticoid-induced osteoporosis (GIOP). Further analysis demonstrated that osteolineage cells transfer mitochondria to osteoclastic lineage cells via Miro1 mediated direct contact, and altered the glutathione metabolism, leading to the ferroptosis of osteoclastic lineage cells, thus inhibiting osteoclast activities. These findings revealed an unappreciated mechanism of mitochondrial regulation of skeletal metabolic homeostasis via mitochondria transfer and provide new insights of the mechanism of GIOP progression.
2024-04-08 | GSE225414 | GEO
Project description:Contacts between organelles create microdomains that play major roles in regulating key intracellular activities and signaling pathways, but whether they also regulate systemic functions remains unknown. Here, we report the ultrastructural organization and dynamics of the inter-organellar contact established by rough-Endoplasmic Reticulum closely wrapped around the mitochondria (wrappER). To elucidate the in vivo function of this contact, mouse liver fractions enriched in wrappER-associated-mitochondria are analyzed by transcriptomics, proteomics and lipidomics. The biochemical signature of the wrappER points to a role in the biogenesis of very-low-density lipoproteins (VLDL). Altering wrappER-mitochondria contacts curtails VLDL secretion and increases hepatic fatty acids, lipid droplets and neutral lipid content. Conversely, acute liver-specific ablation of Mttp, the most upstream regulator of VLDL biogenesis, recapitulates this hepatic dyslipidemia phenotype and promotes remodelling of the wrappER-mitochondria contact. The discovery that liver wrappER-mitochondria contacts participate in VLDL biology suggests an involvement of inter-organelle contacts in systemic lipid homeostasis.
2021-03-15 | GSE134777 | GEO
Project description:Mitochondria are central to cellular function, particularly in metabolically active tissues such as skeletal muscle. Nuclear-encoded RNAs typically localise within the nucleus and cytosol but a small population may also translocate to subcellular compartments such as mitochondria. We aimed to investigate the nuclear-encoded RNAs that localise within the mitochondria of skeletal muscle tissue. Intact mitochondria were isolated via immunoprecipitation (IP) followed by enzymatic treatments (RNase-A and proteinase-K) optimised to remove transcripts located exterior to mitochondria, making it amenable for high-throughput transcriptomic sequencing. Whole-transcriptome RNA sequencing of enzymatically-purified mitochondria isolated by IP from skeletal muscle tissue showed a high degree of purity. In summary, we describe a novel, powerful sequencing approach applicable to animal and human tissues and cells that can facilitate the discovery of nuclear-encoded RNA transcripts localised within skeletal muscle mitochondria.
2024-09-11 | GSE276307 | GEO
Project description:Mitochondria are central to cellular function, particularly in metabolically active tissues such as skeletal muscle. Nuclear-encoded RNAs typically localise within the nucleus and cytosol but a small population may also translocate to subcellular compartments such as mitochondria. We aimed to investigate the nuclear-encoded RNAs that localise within the mitochondria of skeletal muscle cells and tissue. Intact mitochondria were isolated via immunoprecipitation (IP) followed by enzymatic treatments (RNase-A and proteinase-K) to remove transcripts located exterior to mitochondria, making it amenable for high-throughput transcriptomic sequencing. Whole-transcriptome RNA sequencing of enzymatically-purified mitochondria isolated by IP from skeletal muscle tissue showed a striking similarity in the degree of purity compared to mitoplast preparations which lack an outer mitochondrial membrane. In summary, we describe a novel, powerful sequencing approach applicable to animal and human tissues and cells that can facilitate the discovery of nuclear-encoded RNA transcripts localised within skeletal muscle mitochondria.
2024-09-11 | GSE276306 | GEO
Project description:Exclusion of Parkin from mitochondria of perinatal cardiomyocytes interrupts structural and molecular transformations essential to normal perinatal-adult mitochondrial replacement. mRNA-sequencing from cardiac total RNA was performed at P1, P21 and 5-week stages of nontransgenic (ntg) and human-Mfn2-overexpressing (Mfn2wt) hearts, and also of tet-off control (tetoff) and human-Mfn2 T111A/S442A-overexpressing (Mfn2AA) hearts. Libraries from all P1 samples were prepared and analyzed together, and similarly all P21 libraries, and all 5-week libraries together. To facilitate comparison across time points by accounting for batch effect, new libraries were prepared starting from total RNA from selected P21 ntg and 5-week ntg hearts subjected to prior analysis, during the same batch preparation as all P1 samples, and analyzed together. Correction for differences observed between libraries prepared from the same total RNA, but at different times, allows comparison across timepoints.
2015-12-04 | E-GEOD-68921 | biostudies-arrayexpress