Ontology highlight
ABSTRACT:
PROVIDER: PRJNA397951 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR5927160.fastq.gz | Fastqsanger.gz | |||
| SRR5927161.fastq.gz | Fastqsanger.gz | |||
| SRR5927162.fastq.gz | Fastqsanger.gz | |||
| SRR5927163.fastq.gz | Fastqsanger.gz | |||
| SRR5927164.fastq.gz | Fastqsanger.gz |
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Project description:To determine how the mtDNA load at the beginning of tumorigenesis affects the DNA methylation patterns of TRFs during tumourigenesis. Different loads of mtDNA at the beginning of tumourigenesis have limited impact on the copy number variation contributing to tumorigenesis.
2018-12-31 | GSE98366 | GEO
Project description:How the mtDNA load at the beginning of tumorigenesis affects tumourigenesis
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Project description:This study characterized variations in the methylation profile of mitochondrial DNA (mtDNA) during initial bovine embryo development and correlated the presence of methylation with mtDNA transcription. Bovine oocytes were obtained from abattoir ovaries and submitted to in vitro culture procedures. Oocytes and embryos were collected at various stages (immature oocyte, IM; mature oocyte, MII; zygote, ZY; 4-cells, 4C; 16-cells, 16C and blastocysts, BL). Total DNA (including mtDNA) was used for Whole Genome Enzymatic Methyl Sequencing and for quantification of mtDNA copy number. Extracted RNA was used for quantification of mitochondrial transcripts (ND6, CYTB, tRNA-Phe and tRNA-Gln) using Droplet Digital PCR. The number of mtDNA copies per oocyte/embryo was found to be similar, while methylation levels in mtDNA varied among stages. Higher total methylation levels were found mainly at 4C and 16C. In specific gene regions, higher methylation levels were also observed at 4C and 16C (ND6, CYTB and tRNA-Phe), as well as an inverse correlation with the quantity of transcripts for these regions. This is a first description of epigenetic changes occurring in mtDNA during early embryonic development. Our results indicate that methylation might regulate the mtDNA transcription at a local level, particularly around the time of embryonic genome activation.
2024-04-24 | GSE230476 | GEO
Project description:In virtually all eukaryotes, the mitochondrial genome (mitochondrial DNA, mtDNA) encodes proteins necessary for oxidative phosphorylation (OXPHOS) and the RNA machinery required for their synthesis inside the mitochondria. Appropriate regulation of mtDNA copy number and expression is essential for ensuring the correct stoichiometric formation of OXPHOS complexes assembled from both nuclear- and mtDNA-encoded subunits. The mechanisms of mtDNA regulation are not completely understood but are essential to organismal viability and lifespan. Here, using multiple approaches, we identify the presence of N6-methylation of adenosine (6mA) on the mtDNA of diverse animal and plant species. Importantly, we also demonstrate that this modification is regulated in C. elegans by the DNA methyltransferase DAMT-1, and DNA demethylase ALKB-1, which localize to mitochondria. Misregulation of mtDNA 6mA through targeted overexpression of these enzymatic activities inappropriately alters mtDNA copy number and transcript levels, impairing OXPHOS function and producing increased oxidative stress, as well as a shortened lifespan. Compounding defects in mtDNA regulation, reductions in mtDNA 6mA methylation promote the propagation of a deleterious mitochondrial genome across generations. Together, these results reveal that mtDNA 6mA is highly conserved among eukaryotes and regulates lifespan by influencing mtDNA copy number, expression, and heritable mutation levels in vivo.
2024-08-11 | GSE272419 | GEO
Project description:Mammalian mitochondrial DNA (mtDNA) is coated with mitochondrial transcription factor A (TFAM) and compacted into nucleoids. TFAM is not only the main component of mitochondrial nucleoids but its levels can also control mtDNA copy number. Here we show that the TFAM-to-mtDNA ratio is critical for maintaining normal mtDNA expression in different tissues of the mouse. BAC transgenic mice with a 1.5-fold increase in TFAM protein levels maintain a normal TFAM-to-mtDNA ratio in different tissues and as a consequence mitochondrial gene expression, nucleoid distribution and whole animal metabolism are all unaltered. In contrast, mice expressing TFAM from the CAG promoter in the ROSA26 locus have 4.5-fold increase of TFAM protein levels in heart and skeletal muscle and develop pathology leading to early postnatal lethality. The TFAM-to-mtDNA ratio varies widely between tissues in these mice and is very high in skeletal muscle where it causes strong repression of mtDNA expression and deficient oxidative phosphorylation (OXPHOS) despite normal mtDNA levels. In heart, mtDNA copy number is increased leading to a near normal TFAM-to-mtDNA ratio and maintained OXPHOS capacity. In the liver, mtDNA expression is maintained despite increased TFAM levels and normal mtDNA levels. Here, tissue-specific induction of the LONP1 protease and mitochondrial RNA polymerase (POLRMT) expression counteracts the silencing effect of high TFAM levels. We conclude that the TFAM-to-mtDNA ratio has an important role in maintaining mtDNA expression in vivo. TFAM acts as a general repressor of mtDNA expression and this effect can be counterbalance by tissue-specific expression of regulatory factors.
2021-08-18 | PXD023050 | Pride
Project description:Somatic mtDNA mutations are heavily implicated as important drivers of ageing and age-related diseases. Their pathological effect can be partially counteracted by increasing the absolute amount of wild-type mtDNA via moderately upregulating TFAM, a protein important for mtDNA packaging and expression. However, strong TFAM overexpression can also have detrimental effects as it results in hypercompaction of the mtDNA and subsequent impairment of mtDNA gene expression. In this study, we have experimentally addressed the propensity of moderate TFAM modulation to improve the premature ageing phenotypes of mtDNA mutator mice, carrying random mtDNA mutations. Surprisingly, we detect tissue-specific endogenous compensatory mechanisms acting in mtDNA mutator mice which largely affects the outcome of TFAM modulation. Accordingly, moderate overexpression of TFAM can have both negative and beneficial effects in different tissues of mtDNA mutator mice. We see a similar behavior for moderate TFAM reduction, which improves brown adipocyte tissue homeostasis, while other tissues are largely unaffected. Our findings highlight that regulation of copy number and gene expression of mtDNA is complex and cause tissue-specific effects that should be considered when modulating TFAM levels. Additionally, we suggest that TFAM is not the sole determinant of mtDNA copy number in situations where OXPHOS is compromised but other important players must be involved.
2025-02-17 | PXD054598 | Pride
Project description:How individual genes are regulated from a mitochondrial polycistronic transcript to have variable expression remains an enigma. Here, through bisulfite sequencing and strand-specific mapping, we show mitochondrial genomes in human and other animals were strongly biased to light (L)-strand non-CpG methylation with conserved peak loci preferentially located at gene-gene boundaries, which was also independently validated by MeDIP and FspEI digestion. Such mtDNA methylation patterns are conserved across different species and developmental stages, but display dynamic local or global changes during development and aging. Knockout of DNMT3A alone perturbed mtDNA regional methylation patterns, but not global levels, and altered mitochondrial gene expression, copy number, and oxygen respiration. Overexpression of DNMT3A strongly increased mtDNA methylation and strand bias. Overall, methylation at gene body and boundaries was negatively associated with mitochondrial transcript abundance and also polycistronic transcript processing. Furthermore, HPLC-MS confirmed the methylation signals on mitochondria DNA. Together, these data provide high-resolution mtDNA methylation maps that revealed a strand specific non-CpG methylation, its dynamic regulation and its impact on the polycistronic mitochondrial transcript processing.
2019-08-22 | GSE133962 | GEO
Project description:How individual genes are regulated from a mitochondrial polycistronic transcript to have variable expression remains an enigma. Here, through bisulfite sequencing and strand-specific mapping, we show mitochondrial genomes in human and other animals were strongly biased to light (L)-strand non-CpG methylation with conserved peak loci preferentially located at gene-gene boundaries, which was also independently validated by MeDIP and FspEI digestion. Such mtDNA methylation patterns are conserved across different species and developmental stages, but display dynamic local or global changes during development and aging. Knockout of DNMT3A alone perturbed mtDNA regional methylation patterns, but not global levels, and altered mitochondrial gene expression, copy number, and oxygen respiration. Overexpression of DNMT3A strongly increased mtDNA methylation and strand bias. Overall, methylation at gene body and boundaries was negatively associated with mitochondrial transcript abundance and also polycistronic transcript processing. Furthermore, HPLC-MS confirmed the methylation signals on mitochondria DNA. Together, these data provide high-resolution mtDNA methylation maps that revealed a strand specific non-CpG methylation, its dynamic regulation and its impact on the polycistronic mitochondrial transcript processing.
2019-08-22 | GSE133961 | GEO
Project description:How individual genes are regulated from a mitochondrial polycistronic transcript to have variable expression remains an enigma. Here, through bisulfite sequencing and strand-specific mapping, we show mitochondrial genomes in human and other animals were strongly biased to light (L)-strand non-CpG methylation with conserved peak loci preferentially located at gene-gene boundaries, which was also independently validated by MeDIP and FspEI digestion. Such mtDNA methylation patterns are conserved across different species and developmental stages, but display dynamic local or global changes during development and aging. Knockout of DNMT3A alone perturbed mtDNA regional methylation patterns, but not global levels, and altered mitochondrial gene expression, copy number, and oxygen respiration. Overexpression of DNMT3A strongly increased mtDNA methylation and strand bias. Overall, methylation at gene body and boundaries was negatively associated with mitochondrial transcript abundance and also polycistronic transcript processing. Furthermore, HPLC-MS confirmed the methylation signals on mitochondria DNA. Together, these data provide high-resolution mtDNA methylation maps that revealed a strand specific non-CpG methylation, its dynamic regulation and its impact on the polycistronic mitochondrial transcript processing.
2019-08-22 | GSE133960 | GEO
Project description:How individual genes are regulated from a mitochondrial polycistronic transcript to have variable expression remains an enigma. Here, through bisulfite sequencing and strand-specific mapping, we show mitochondrial genomes in human and other animals were strongly biased to light (L)-strand non-CpG methylation with conserved peak loci preferentially located at gene-gene boundaries, which was also independently validated by MeDIP and FspEI digestion. Such mtDNA methylation patterns are conserved across different species and developmental stages, but display dynamic local or global changes during development and aging. Knockout of DNMT3A alone perturbed mtDNA regional methylation patterns, but not global levels, and altered mitochondrial gene expression, copy number, and oxygen respiration. Overexpression of DNMT3A strongly increased mtDNA methylation and strand bias. Overall, methylation at gene body and boundaries was negatively associated with mitochondrial transcript abundance and also polycistronic transcript processing. Furthermore, HPLC-MS confirmed the methylation signals on mitochondria DNA. Together, these data provide high-resolution mtDNA methylation maps that revealed a strand specific non-CpG methylation, its dynamic regulation and its impact on the polycistronic mitochondrial transcript processing.
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