Project description:Here we determine the map of RNA methylation (m6A) in mouse embrionic stem cells, and Mettl3 knock out cells Examination of m6A modification sites on the transcriptome of mouse Embryonic stem cells and Embryonic Mettl3 knock out cells, using a m6A specific antibody.
Project description:Liver-specific deficiency of Mettl3 causes liver injury. By performing RNA sequencing (RNA-seq) analysis on the Mettl3-deficient versus control livers, we identified the potential target genes that were closely associated with the liver phenotype in liver-specific Mettl3 knockout mice. RNA-seq analysis revealed extensive metabolic reprogramming in Mettl3-deficient livers. These results demonstrated that Mettl3 coordinates metabolic homeostasis and functional maturation during postnatal liver development.
Project description:The N6-methyladenosine (m6A) mRNA modification and the mitochondrial respiratory chain (MRC) hold paramount importance in the advancement of MASLD. This study thoroughly investigates the relationship and impact of m6A mRNA modification and mitochondrial function in the progression of MASLD. Here we report that the mRNA and protein levels of mitochondrial respiratory chain (MRC) subunits showed inconsistent trends in vivo experiments. Abnormal m6A modification and mitochondrial dysfunction in MASLD were attributed to the upregulation of methyltransferase like 3 (Mettl3) and the downregulation of YTH N6-methyladenosine RNA binding protein 1 (YTHDF1) induced by high-fat foods. Mettl3 promoted the MRC's function. However, knockout of the reader protein YTHDF1, which plays a crucial role in the m6A modification process, counteracted the effect of Mettl3 and suppressed MRC. In MASLD, damage to the MRC may be regulated by the Mettl3-m6A-YTHDF1 complex axis, especially by the role of YTHDF1. Our research has offered a novel perspective on the involvement of m6A mRNA methylation in the pathogenesis of MASLD.
Project description:RNA sequencing of livers tissues from control and hepatocyte-specific Mettl3 knockout with ALB-Cre (Mettl3 cKO) mice at different time points after birth.
Project description:Cadmium is an environmental pollutant that has extensive deleterious effects. However, the mechanisms underlying the hepatotoxicity induced by long-term exposure to cadmium remained undefined. In the present study, we explored the role of m6A methylation in the development of cadmium-induced liver disease. We showed a dynamic change of RNA methylation in liver tissue from mice administrated with cadmium chloride (CdCl2) for 3, 6 and 9 months, respectively. Particularly, the METTL3 expression was declined in a time-dependent manner, associated with the degree of liver injury, indicating the involvement of METTL3 in hepatotoxicity induced by CdCl2. Moreover, we established a mouse model with liver-specific over-expression of Mettl3 and administrated these mice with CdCl2 for 6 months. Notably, METTL3 highly expressed in hepatocytes attenuated CdCl2-induced steatosis and liver fibrosis in mice. In vitro assay also showed METTL3 overexpression ameliorated the CdCl2-induced cytotoxicity and activation of primary hepatic stellate cells. Furthermore, transcriptome analysis identified 268 differentially expressed genes both in mice liver tissue treated with CdCl2 for 3 months and 9 months. Among them, 115 genes were predicted to be regulated by METTL3 determined by m6A2Target database. Further analysis revealed the perturbation of metabolic pathway, glycerophospholipid metabolism, ErbB signaling pathway, Hippo signaling pathway, and choline metabolism in cancer, and circadian rhythm, led to hepatotoxicity induced by CdCl2. Collectively, our findings reveal new insight into the crucial role of epigenetic modifications in hepatic diseases caused by long-term exposure to cadmium.
Project description:We show that N6-methyladenosine (m6A), the most abundant internal modification in mRNA/lncRNA with still poorly characterized function, alters RNA structure to facilitate the access of RBM for heterogeneous nuclear ribonucleoprotein C (hnRNP C). We term this mechanism m6A-switch. Through combining PAR-CLIP with Me-RIP, we identify 39,060 m6A-switches among hnRNP C binding sites transcriptome-wide. We show that m6A-methyltransferases METTL3 or METTL14 knockdown decreases hnRNP C binding at 16,582 m6A-switches. Taken together, 2,798 m6A-switches of high confidence are identified to mediate RNA-hnRNP C interactions and affect diverse biological processes including cell cycle regulation. These findings reveal the biological importance of m6A and provide insights into the sophisticated regulation of RNA-RBP interactions through m6A-induced RNA structural remodeling. Measure the m6A methylated hnRNP C binding sites transcriptome-wide by PARCLIP-MeRIP; measure the differential hnRNP C occupancies upon METTL3/METTL14 knockdown by PAR-CLIP; measure RNA abundance and splicing level changes upon HNRNPC, METTL3 and METTL14 knockdown
Project description:we find METTL3 associates with polyribosomes and promotes translation. METTL3 depletion inhibits translation, and both wild-type and catalytically inactive METTL3 promote translation when tethered to the 3' untranslated region (UTR) of a reporter mRNA. Mechanistically, METTL3 enhances mRNA translation through an interaction with the translation initiation machinery. m6A seq in A549 and H1299 cells, RNA seq in METTL3 knockdown cells
Project description:Purpose: The goal of this study is to determine whether hepatic deletion of Mettl3 affects chromatin accessibility. Methods: Liver samples were pooled from livers of Mettl3 HKO and Mettl3 flox/flox mice (n=4 for each group). Nuclei was extracted from liver samples, and the nuclei pellet was resuspended in the Tn5 transposase reaction mix. The transposition reaction was incubated at 37°C for 30 min. Equimolar Adapter1 and Adatper 2 were added after transposition, PCR was then performed to amplify the library. After the PCR reaction, libraries were purified with the AMPure beads and library quality was assessed with Qubit. The clustering of the index-coded samples was performed on a cBot Cluster Generation System using TruSeq PE Cluster Kit v3-cBot-HS (Illumina) according to the manufactuer’s instructions. After cluster generation, the library preparations were sequenced on an Illumina NovaSeq 6000 platform and 150 bp paired-end reads were generated. ATAC-seq analysis was performed using a standard protocol. Results: The hepatic chromatin accessibility in Mettl3 flox/flox and HKO mice were characterized.
Project description:METTL3 is essential for ESC differentiation and embryonic development, and its dysregulation is linked to various diseases including metabolic disorders and cancer. However, the consequence of m6A perturbation in the mammalian liver is not understood. Here, we provide insight into this by generating mice M3LKO (Mettl3fl/fl; Alb-Cre) mice carrying a hepatocyte-specific deletion of Mettl3.
Project description:To investigate the role of METTL3-mediated m6A modification in liver, we performed m6A-sequencing to map the m6A modification in liver tissues of wild type (WT) and liver-sepcific Mettl3-KO mice.