Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA330795 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR3938822.fastq.gz | Fastqsanger.gz | |||
| SRR3938823.fastq.gz | Fastqsanger.gz | |||
| SRR3938824.fastq.gz | Fastqsanger.gz |
Items per page: 5 1 - 3 of 3 |
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2016-08-09 | E-GEOD-84664 | biostudies-arrayexpress
Project description:Mitochondrial gene expression uses a non-universal genetic code in mammals. Besides reading the conventional AUG codon, mitochondrial (mt-)tRNAMet mediates incorporation of methionine on AUA and AUU codons during translation initiation and on AUA codons during elongation. We show that the RNA methyltransferase NSUN3 localises to mitochondria and interacts with mt-tRNAMet to methylate cytosine 34 (C34) at the wobble position. NSUN3 specifically recognises the anticodon stem loop (ASL) of the tRNA, explaining why a mutation that compromises ASL basepairing leads to disease. We further identify ALKBH1/ABH1 as the dioxygenase responsible for oxidising m5C34 of mt-tRNAMet to generate an f5C34 modification. In vitro codon recognition studies with mitochondrial translation factors reveal preferential utilization of m5C34 mt-tRNAMet in initiation. Depletion of either NSUN3 or ABH1 strongly affects mitochondrial translation in human cells, implying that modifications generated by both enzymes are necessary for mt-tRNAMet function. Together, our data reveal how modifications in mt-tRNAMet are generated by the sequential action of NSUN3 and ABH1, allowing the single mitochondrial tRNAMet to recognise the different codons encoding methionine.
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Project description:5-Formylcytidine (f5C) is one type of post-transcriptional RNA modifi-cations, which is known at the wobble position of tRNA in mitochon-dria and essential for mitochondrial protein synthesis. Here, we show a method to detect f5C modifications in RNA and a transcriptome-wide f5C mapping technique, named f5C-seq. It is developed based on the treatment of pyridine borane, which can reduce f5C to 5,6-dihydrouracil (DHU), thus inducing C-to-T transition in f5C sites during PCR to achieve single-base resolution detection. Thousands of f5C sites were identified after mapping in Saccharomyces cerevisiae by f5C-seq. Moreover, codon composition demonstrated a preference for f5C within wobble sites in mRNA, suggesting the potential role in regulation of translation. These findings expand the scope of the understanding of cytosine modifications in mRNA. Reference build: S288C_reference_genome_R64-2-1_20150113
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Project description:Somatic variation contributes to biological heterogeneity by modulating the cellular proclivity to differentiate, expand, adapt, or die. While large-scale sequencing efforts have revealed the foundational role of somatic variants to drive human tumor evolution, our understanding of the contribution of somatic variation to modulate cellular fitness in non-malignant contexts remains understudied. Here, we identify a somatic synonymous variant (m.7076A>G) in the mitochondrial DNA (mtDNA) encoded cytochrome c-oxidase subunit 1 gene (COX1), which was present at homoplasmy in 47% of immune cells from a healthy donor. Using single-cell multi-omics, we discover highly specific selection against the m.7076G mutant allele in the CD8+ effector memory T cell compartment in vivo, reminiscent of selection observed for pathogenic mtDNA alleles and indicative of lineage-specific metabolic vulnerabilities. Due to the limited transfer RNA (tRNA) pool in mitochondria, the m.7076G mutant allele requires wobble-dependent translation whereas the wildtype m.7076A allele can translate via Watson-Crick-Franklin (WCF) base-pairing. Mitochondrial ribosome profiling revealed that the synonymous m.7076G mutant allele altered codon-anticodon affinity by 33% at the wobble position, stalling translation at the glycine residue within COX1 encoded at m.7076. Leveraging population-based sequencing analyses, we identify evidence of synonymous somatic variants in tumor genomes and dozens of germline variants associated with complex diseases, suggesting broad functional effects of synonymous variation altering codon affinity across the mitochondrial genome. Together, these results provide a new ontogeny for mitochondrial genetic variation and elucidate a framework whereby somatic variation can impact cell state transitions in a lineage-specific manner.
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Project description:Somatic variation contributes to biological heterogeneity by modulating the cellular proclivity to differentiate, expand, adapt, or die. While large-scale sequencing efforts have revealed the foundational role of somatic variants to drive human tumor evolution, our understanding of the contribution of somatic variation to modulate cellular fitness in non-malignant contexts remains understudied. Here, we identify a somatic synonymous variant (m.7076A>G) in the mitochondrial DNA (mtDNA) encoded cytochrome c-oxidase subunit 1 gene (COX1), which was present at homoplasmy in 47% of immune cells from a healthy donor. Using single-cell multi-omics, we discover highly specific selection against the m.7076G mutant allele in the CD8+ effector memory T cell compartment in vivo, reminiscent of selection observed for pathogenic mtDNA alleles and indicative of lineage-specific metabolic vulnerabilities. Due to the limited transfer RNA (tRNA) pool in mitochondria, the m.7076G mutant allele requires wobble-dependent translation whereas the wildtype m.7076A allele can translate via Watson-Crick-Franklin (WCF) base-pairing. Mitochondrial ribosome profiling revealed that the synonymous m.7076G mutant allele altered codon-anticodon affinity by 33% at the wobble position, stalling translation at the glycine residue within COX1 encoded at m.7076. Leveraging population-based sequencing analyses, we identify evidence of synonymous somatic variants in tumor genomes and dozens of germline variants associated with complex diseases, suggesting broad functional effects of synonymous variation altering codon affinity across the mitochondrial genome. Together, these results provide a new ontogeny for mitochondrial genetic variation and elucidate a framework whereby somatic variation can impact cell state transitions in a lineage-specific manner.
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