NSUN2 introduces 5-methylcytosines in mammalian mitochondrial tRNAs
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE132020 | GEO | 2019/06/19
REPOSITORIES: GEO
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Project description:NSUN2 introduces 5-methylcytosines in mammalian mitochondrial tRNAs
| PRJNA545637 | ENA
Project description:Expression of human mitochondrial DNA is indispensable for proper function of the oxidative phosphorylation machinery. The mitochondrial genome encodes 22 tRNAs, 2 rRNAs and 11 mRNAs and their post-transcriptional modification constitutes one of the key regulatory steps during mitochondrial gene expression. Cytosine-5 methylation (m5C) has been detected in mitochondrial transcriptome, however its biogenesis has not been investigated in details. Mammalian NOP2/Sun RNA Methyltransferase Family Member 2 (NSUN2) has been characterized as an RNA methyltransferase introducing m5C in nuclear-encoded tRNAs, mRNAs and microRNAs and associated with cell proliferation and differentiation, with pathogenic variants in NSUN2 being linked to neurodevelopmental disorders. Here we employ spatially restricted proximity labelling and immunodetection to demonstrate that NSUN2 is imported into the matrix of mammalian mitochondria. Using three genetic models for NSUN2 inactivation-knockout mice, patient-derived fibroblasts and CRISPR/Cas9 knockout in human cells-we show that NSUN2 is necessary for the generation of m5C at positions 48, 49 and 50 of several mammalian mitochondrial tRNAs. Finally, we show that inactivation of NSUN2 does not have a profound effect on mitochondrial tRNA stability and oxidative phosphorylation in differentiated cells. We discuss the importance of the newly discovered function of NSUN2 in the context of human disease.
| S-EPMC6822013 | biostudies-literature
Project description:Epitranscriptomic mechanisms linking the brain proteome to cognition and complex behaviors essentially remain unexplored. Here, we describe bi-directional changes in depression-related behaviors after genetic disruption of neuronal tRNA cytosine methylation, including conditional ablation and transgene-derived overexpression of NOL1/NOP2/SUN domain 2 (Nsun2) in the prefrontal cortex (PFC). Neuronal Nsun2-deficiency was associated with a sharp drop in tRNA m5C levels, resulting in significant deficits in expression of 70% (7/10) of tRNAGlyGCC, GlyCCC GlyTCC isodecoders, while expression changes in non-glycinergic tRNAs were minimal (4/152). Altogether, 1488/5820 proteins were sensitive to neuronal Nsun2-deficiency, in conjunction with GCC and CCC codon-specific defects in translational efficiencies and loss of Gly-rich proteins critical for glutamatergic neurotransmission, resulting in impaired synaptic signaling at PFC pyramidal neurons and impairments in contextual fear memory. These distortions in the neuronal translatome were associated with an adaptive, 2.46-fold up-regulation in PFC glycine levels with increased expression of multiple enzymes in the glycine biosynthetic pathway. These findings highlight the methylation sensitivity of glycinergic tRNAs in the adult PFC and link synaptic plasticity and complex behaviors to epitranscriptomic regulation of cognate tRNAs and the proteomic homeostasis associated with specific amino acids.
2021-07-01 | GSE165202 | GEO
Project description:Post-transcriptional modifications in mitochondrial tRNAs (mt-tRNAs) play critical roles in mitochondrial protein synthesis, which produces respiratory chain complexes. In this study, we took advantage of mass spectrometric analysis to map 5-methylcytidine (m5C) at positions 48-50 in eight mouse and six human mt-tRNAs. We also confirmed the absence of m5C in mt-tRNAs isolated from Nsun2 knockout (KO) mice, as well as from NSUN2 KO human culture cells. In addition, we successfully reconstituted m5C at positions 48-50 of mt-tRNA in vitro with NSUN2 protein in the presence of S-adenosylmethionine. Although NSUN2 is predominantly localized to the nucleus and introduces m5C into cytoplasmic tRNAs and mRNAs, structured illumination microscopy clearly revealed NSUN2 foci inside mitochondria. These observations provide novel insights into the role of NSUN2 in the physiology and pathology of mitochondrial functions.
| S-EPMC6895283 | biostudies-literature
Project description:Background: As a widespread post-transcriptional RNA modification, N5-methylcytosine (m5C) is implicated in a variety of cellular responses and processes that regulate RNA metabolism. Despite this, a clear understanding of m5C modification’s role and mechanism in angiogenesis is still lacking. Methods: Single-cell RNA sequencing data was analyzed to determine expression of m5C methylase NSUN2. m5C levels were determined by mRNA isolation and anti-m5C dot blot in both hypoxia-induced endothelial cells (ECs) and laser-induced choroidal neovascularization (CNV). In addition, endothelial cell and endothelium‐specific NSUN2‐knockout mouse model were used to investigate the effect of NSUN2 silence on angiogenic phenotype. Genome-wide multiomics analyses were performed to identify the functional target of NSUN2, including proteomic analysis, transcriptome screening and m5C-methylated RNA immunoprecipitation sequencing (m5C-meRIP-seq). CUT&Tag sequencing was performed to test the histone lactylation signal in the promoter region of NSUN2. Finally, AAV-mediated short hairpin RNAi knockdown of NSUN2 gene expression (AAV-shNSUN2) was constructed to investigate the effect of inhibiting CNV. Results: First, we discovered that m5C methylase NSUN2 expression level and mRNA m5C level were significantly higher in CNV-ECs than in normal ECs. NSUN2 knockdown in ECs inhibited proliferative, migration, and tube formation activities of ECs. Moreover, compared with EC NSUN2flox/flox mice, EC-specific NSUN2-deficient (EC NSUN2-/-) mice displayed less retinal vascular leakage after laser induction. Through multiomics analyses, we subsequently identified A-kinase anchoring protein 2 (AKAP2), a scaffolding protein which isolate Protein kinase A (PKA) to specific subcellular locations through binding to its regulatory subunit, as a downstream candidate target of NSUN2 in ECs. Overexpression of exogenous AKAP2 markedly reversed the inhibitory phenotypes in NSUN2-deficient ECs. Interestingly, laser induced NSUN2 up-regulation was driven by lactate-mediated lactylation on histone H3K18. In CNV models, AAV-mediated repression of NSUN2 modulated highly retinal vascular leakage and choroidal thickness. Conclusion: Overall, our findings indicate that NSUN2 is a novel therapeutic target for choroidal neovascularization.
2024-05-19 | GSE267662 | GEO
Project description:Background: As a widespread post-transcriptional RNA modification, N5-methylcytosine (m5C) is implicated in a variety of cellular responses and processes that regulate RNA metabolism. Despite this, a clear understanding of m5C modification’s role and mechanism in angiogenesis is still lacking. Methods: Single-cell RNA sequencing data was analyzed to determine expression of m5C methylase NSUN2. m5C levels were determined by mRNA isolation and anti-m5C dot blot in both hypoxia-induced endothelial cells (ECs) and laser-induced choroidal neovascularization (CNV). In addition, endothelial cell and endothelium‐specific NSUN2‐knockout mouse model were used to investigate the effect of NSUN2 silence on angiogenic phenotype. Genome-wide multiomics analyses were performed to identify the functional target of NSUN2, including proteomic analysis, transcriptome screening and m5C-methylated RNA immunoprecipitation sequencing (m5C-meRIP-seq). CUT&Tag sequencing was performed to test the histone lactylation signal in the promoter region of NSUN2. Finally, AAV-mediated short hairpin RNAi knockdown of NSUN2 gene expression (AAV-shNSUN2) was constructed to investigate the effect of inhibiting CNV. Results: First, we discovered that m5C methylase NSUN2 expression level and mRNA m5C level were significantly higher in CNV-ECs than in normal ECs. NSUN2 knockdown in ECs inhibited proliferative, migration, and tube formation activities of ECs. Moreover, compared with EC NSUN2flox/flox mice, EC-specific NSUN2-deficient (EC NSUN2-/-) mice displayed less retinal vascular leakage after laser induction. Through multiomics analyses, we subsequently identified A-kinase anchoring protein 2 (AKAP2), a scaffolding protein which isolate Protein kinase A (PKA) to specific subcellular locations through binding to its regulatory subunit, as a downstream candidate target of NSUN2 in ECs. Overexpression of exogenous AKAP2 markedly reversed the inhibitory phenotypes in NSUN2-deficient ECs. Interestingly, laser induced NSUN2 up-regulation was driven by lactate-mediated lactylation on histone H3K18. In CNV models, AAV-mediated repression of NSUN2 modulated highly retinal vascular leakage and choroidal thickness. Conclusion: Overall, our findings indicate that NSUN2 is a novel therapeutic target for choroidal neovascularization.
2024-05-19 | GSE267661 | GEO
Project description:The role of transfer (t)RNA cytosine methyl-transferases as epitranscriptomic regulators of brain proteomes remains unexplored. We report that fear memory and antidepressant-like behaviors are highly sensitive to bi-directional changes in Nsun2 tRNA methyltransferase activity in prefrontal cortex (PFC) neurons. Nsun2-deficient mutant cortex showed a selective deficit in multiple glycine tRNAs, resulting in codon-specific shifts in translational efficiencies and a distorted proteomic landscape with deficits in glycine-rich neuronal proteins impacting synaptic signaling and behavior.
2021-07-02 | PXD023437 | Pride
Project description:5-methylcytosine (m5C) modification ubiquitously occurs on mammalian mRNAs and plays important roles in multiple biological processes. Currently, the role of m5C in cancer initiation and progression is gaining more and more research attention, but the detailed mechanism remains unclear. As an m5C methyltransferase with unique mRNA catalytic activity, NSUN2 was found to be highly expressed in multiple cancers including gastric, bladder, gallbladder, and breast cancers, suggesting NSUN2 might exert oncogenic properties through affecting m5C levels in cancer cells. Therefore, to understand the potential roles of RNA m5C modification in tumorigenesis of cervical cancer, we established NSUN2 stable knockdown CaSki cell, and perform RNA-seq and RNA-BisSeq to figure out the possible pathway involved in cervical cancer development.
2021-09-24 | GSE184621 | GEO
Project description:5-methylcytosine (m5C) RNA modification installed by methyltransferase NSUN2 regulates gene expression and cell fate. Retinoblastoma (RB) is the most common primary intraocular tumor in children. However, the functional role of m5C modification in retinoblastoma remains unclear. Here, we show that 5-methylcytosine significantly promotes the progression of retinoblastoma. Retinoblastoma samples showed increased m5C levels, indicating a poor prognosis. Changes in global m5C modification were highly associated with tumor progression in vitro and in vivo. Mechanistically, NSUN2 stabilized the methylated PFAS mRNA, a tumor promoter in retinoblastoma. Our work uncovers a critical function for m5C methylation in retinoblastoma and provides additional insight into the understanding of m5C modification.
2022-10-07 | GSE214685 | GEO
Project description:Background: Colorectal cancer (CRC) is a harmful cancer with high morbidity and poor prognosis. There is growing evidence that RNA methylation is closely related to the occurrence of cancer and its malignant biological behavior. N6-methyladenosine (m6A) methylation is the most common RNA modification in eukaryotes, and its multiple regulatory mechanisms in CRC have been elucidated from multiple perspectives. At the same time, the role of 5-methylcytosine (m5C), another important and widely distributed methylation modification, in CRC is far from being elucidated. Methods: In this study, we used RNA immunoprecipitation sequencing combined with bioinformatics methods to identify the m5C peaks on messenger RNA (mRNA) in HCT15 cells and sh-NSUN2 HCT15 cells, understand which transcripts are modified by m5C, and characterize the distribution of m5C modifications. In addition, we performed further bioinformatics analysis of the detected data to initially clarify the potential function of these m5C-modified transcripts. Results: We found significant differences in the distribution of m5C between HCT15 cells and sh-NSUN2 HCT15 cells, suggesting that m5C is likely to play a key role in the occurrence and development of CRC. Furthermore, Gene Ontology (GO) enrichment analysis showed that genes altered by m5C were mainly enriched in phylogeny, synaptic membrane, and transcription factor binding.The Kyoto Encyclopedia of Genes and Genomes（KEGG）pathway analysis showed that the genes altered by m5C are enriched in ECM receptor interaction pathway, the circadian pathway, and the cAMP signaling pathway. Conclusions: Here, our study preliminarily revealed the different distribution patterns of m5C between HCT15 cell and sh-NSUN2 HCT15 cell. Our results open a new window to understand the role of m5C RNA methylation of mRNA in the development of CRC.
2023-03-02 | GSE226129 | GEO