Dataset Information

METTL4 catalyzes m6Am methylation in U2 snRNA to regulate pre-mRNA splicing

ABSTRACT: N6-methylation of 2’-O-methyladenosine (Am) in RNA occurs in eukaryotic cells to generate N6,2’-O-dimethyladenosine (m6Am). Identification of the methyltransferase responsible for m6Am catalysis has accelerated studies on the function of m6Am in RNA processing. While m6Am is generally found in the first transcribed nucleotide of mRNAs, the modification is also found internally within U2 snRNA. However, the writer required for catalyzing internal m6Am formation had remained elusive. By sequencing transcriptome-wide RNA methylation at single-base-resolution, we identified human METTL4 as the writer that directly methylates Am at U2 snRNA position 30 into m6Am. We found that METTL4 localizes to the nucleus and its conserved methyltransferase catalytic site is required for U2 snRNA methylation. By sequencing human cells with overexpressed Mettl4, we determined METTL4’s in vivo target RNA motif specificity. In the absence of Mettl4 in human cells, U2 snRNA lacks m6Am thereby affecting a subset of splicing events that exhibit specific features such as overall 3’ splice-site weakness with certain motif positions more affected than others. This study establishes that METTL4 methylation of U2 snRNA regulates splicing of specific pre-mRNA transcripts.

ORGANISM(S): Homo sapiens

PROVIDER: GSE144745 | GEO | 2020/08/17

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Project description:BACKGROUND: Mitochondrial dysfunction is a key factor in the development of atherogenesis. Methyltransferase-like protein 4 (METTL4) mediates N6-deoxyadenosine (6mA) methylation of mammalian mitochondrial DNA (mtDNA). However, the role of METTL4-mediated mitoepigenetic regulation in atherosclerosis is still unknown. This study aims to investigate the potential involvement of METTL4 in atherosclerosis, explore the underlying mechanism, and develop targeted strategies for treating atherosclerosis. METHODS: Expression levels of mtDNA 6mA and METTL4 were determined in atherosclerotic lesions. We explored the mechanism of METTL4 involvement in atherosclerosis using Mettl4Mac-KO-Apoe-/- and Mettl4MUT-Apoe-/- mice and cell models, as well as bone marrow transplantation. Natural compound libraries were screened to identify potent METTL4 antagonists. In addition, bioinspired proteolysis-targeting (PROTAC) technology targeting macrophages within plaques was used to increase the efficacy of the METTL4 antagonist. RESULTS: The expression levels of mtDNA 6mA and METTL4 were significantly increased in plaque macrophages. Mettl4Mac-KO-Apoe-/- mice displayed suppressed mtDNA 6mA levels and atherosclerotic progression, which were reversed by METTL4 restoration via bone marrow transplantation (n = 6). Mechanistically, elevated METTL4 expression reduces MT-ATP6 expression by suppressing its transcription, thereby impairing the activity of mitochondrial respiration chain complex V. This disruption leads to the accumulation of excess protons in the mitochondrial intermembrane space, causing mitochondrial dysfunction. Consequently, mtDNA is released into the cytoplasm, ultimately triggering inflammasome activation. All results were reversed by the mutation in the METTL4 methyltransferase active site. Mettl4MUT-Apoe-/- mice showed suppressed mtDNA 6mA levels and atherosclerotic progression, and repaired mitochondrial function of macrophage, which were reversed by METTL4 restoration via bone marrow transplantation (n = 6). Pemetrexed (PEM) was identified as the first METTL4 antagonist to effectively alleviate atherosclerotic progression. Furthermore, we generated a proteolysis-targeting chimera drug based on PEM (PROTAC-PEM) that specifically targeting METTL4 in macrophages within plaques, showing a promising therapeutic effect on atherosclerosis. CONCLUSIONS: This study revealed a novel mechanism by which mtDNA 6mA orchestrated mitochondrial function-related gene expression in macrophages, thereby promoting atherosclerosis. Through various experimental techniques, such as gene manipulation, pharmacological inhibition and PROTAC, this study demonstrated that mtDNA 6mA and its specific enzyme METTL4 hold potential as therapeutic targets for atherosclerosis.

Dataset Information

METTL4 catalyzes m6Am methylation in U2 snRNA to regulate pre-mRNA splicing

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets