A functional twintron, “zombie” twintrons and a hypermobile group II intron invading itself in plant mitochondria
Ontology highlight
ABSTRACT:
PROVIDER: PRJEB34500 | ENA |
REPOSITORIES: ENA
Similar Datasets
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:Group II introns are large catalytic RNAs (ribozymes) which are found in bacteria and organellar genomes of several lower eukaryotes, but are particularly prevalent within the mitochondrial genomes (mtDNA) in plants, where they reside in numerous critical genes. Their excision is therefore essential for mitochondria biogenesis and respiratory functions, and is facilitated in vivo by various protein cofactors. Typical group II introns are classified as mobile genetic elements, consisting of the self-splicing ribozyme and its intron-encoded maturase protein. A hallmark of maturases is that they are intron specific, acting as cofactors which bind their own cognate containing pre-mRNAs to facilitate splicing. However, the plant organellar introns have diverged considerably from their bacterial ancestors, such as they lack many regions which are necessary for splicing and also lost their evolutionary related maturase ORFs. In fact, only a single maturase has been retained in the mtDNA of various angiosperms: the matR gene encoded in the fourth intron of the NADH-dehydrogenase subunit 1 (nad1 intron 4). Their degeneracy and the absence of cognate ORFs suggest that the splicing of plant mitochondria introns is assisted by trans-acting cofactors. Interestingly, in addition to MatR, the nuclear genomes of angiosperms also harbor four genes (nMat 1-4), which are closely related to maturases and contain N-terminal mitochondrial localization signals. Recently, we established the roles of two of these paralogs in Arabidopsis, nMAT1 and nMAT2, in the splicing of mitochondrial introns. In addition to the nMATs, genetic screens led to the identification of other genes encoding various factors, which are required for the splicing and processing of mitochondrial introns in plants. In this review we will summarize recent data on the splicing and processing of mitochondrial introns and their implication in plant development and physiology, with a focus on maturases and their accessory splicing cofactors.
| S-EPMC3927076 | biostudies-literature
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:To reveal an unappreciated mechanism of mitochondrial regulation of skeletal metabolic homeostasis via mitochondria transfer and provide new insights of the mechanism of glucocorticoid-induced osteoporosis progression.
2024-04-08 | GSE248687 | GEO
Project description:Intron evolution in Saccharomycetaceae
| PRJNA253808 | ENA
Project description:In the earliest step of spliceosome assembly, the two splice sites flanking an intron are brought into proximity by U1 snRNP and U2AF. The mechanism that facilitates this intron looping is poorly understood. Using a CRISPR interference-based approach to halt RNA polymerase II transcription in the middle of introns, we discovered that the 5 splice site base pairs with a U1 snRNA that is tethered to RNA polymerase II during intron synthesis. Correlation with splicing outcomes demonstrate that these associations are functional. The interactions between 5 splice sites, U1 snRNP, and elongating RNA polymerase II occurs genome-wide. Our findings reveal that during intron synthesis the upstream 5 splice site remains attached to the transcriptional machinery and is thus brought into proximity of the 3 splice site to enable rapid splicing.
2021-06-16 | GSE144906 | GEO
Project description:In the earliest step of spliceosome assembly, the two splice sites flanking an intron are brought into proximity by U1 snRNP and U2AF. The mechanism that facilitates this intron looping is poorly understood. Using a CRISPR interference-based approach to halt RNA polymerase II transcription in the middle of introns, we discovered that the 5 splice site base pairs with a U1 snRNA that is tethered to RNA polymerase II during intron synthesis. Correlation with splicing outcomes demonstrate that these associations are functional. The interactions between 5 splice sites, U1 snRNP, and elongating RNA polymerase II occurs genome-wide. Our findings reveal that during intron synthesis the upstream 5 splice site remains attached to the transcriptional machinery and is thus brought into proximity of the 3 splice site to enable rapid splicing.
2021-06-16 | GSE144905 | GEO
Project description:In the earliest step of spliceosome assembly, the two splice sites flanking an intron are brought into proximity by U1 snRNP and U2AF. The mechanism that facilitates this intron looping is poorly understood. Using a CRISPR interference-based approach to halt RNA polymerase II transcription in the middle of introns, we discovered that the 5 splice site base pairs with a U1 snRNA that is tethered to RNA polymerase II during intron synthesis. Correlation with splicing outcomes demonstrate that these associations are functional. The interactions between 5 splice sites, U1 snRNP, and elongating RNA polymerase II occurs genome-wide. Our findings reveal that during intron synthesis the upstream 5 splice site remains attached to the transcriptional machinery and is thus brought into proximity of the 3 splice site to enable rapid splicing.
2021-06-16 | GSE144874 | GEO
Project description:Plant mitochondrial group II introns do not all possess hallmark ribozymic features such as the bulged adenosine involved in lariat formation. To gain insight into their splicing pathways, we have examined the physical form of excised introns in germinating wheat embryos. Using RT-PCR and cRT-PCR, we observed conventional lariats consistent with a two-step transesterification pathway for introns such as nad2 intron 4, but this was not the case for the cox2 intron or nad1 intron 2. For cox2, we detected full-length linear introns, which possess non-encoded 3'terminaladenosines, as well as heterogeneous circular introns, which lack 3' nucleotide stretches. These observations are consistent with hydrolytic splicing followed by polyadenylation as well as an in vivo circularization pathway, respectively. The presence of both linear and circular species in vivo is supported by RNase H analysis. Furthermore, the nad1 intron 2, which lacks a bulged nucleotide at the branchpoint position, comprised a mixed population of precisely full-length molecules and circular ones which also include a short, discrete block of non-encoded nucleotides. The presence of these various linear and circular forms of excised intron molecules in plant mitochondria points to multiple novel group II splicing mechanisms in vivo.
| S-EPMC1464410 | biostudies-literature
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