Linking RNA Methylation with Chromatin Architecture

Numerous different types of nucleic acid modifications have been identified. Especially for many RNA modifications their function(s) and the modifying enzymes (”writers”) are still awaiting identification. To identify novel RNA modifying enzymes we focused our studies on a family of potential methyltransferases. In order to identify the complexes in which these potential enzymes might act we systematically performed immunoprecipitations followed by mass spectrometry. In parallel to that, we used in vitro methyltransferase assays to profile a range of substrates of these potential methyltransferases. Interestingly we found one of these enzymes to methylate non-polyA RNAs. We applied RNA size exclusion chromatography in combination with mass spectrometry and identified the methylation mark as m6A. By performing m6A-IP followed by NGS in wt and the enzyme KO cells we identified a subset of target RNAs and validated them by m6A-IP followed by qPCR. RNA-seq analyses of the methyltransferase KO cell lines indicated global changes in the canonical histones and chromatin-related proteins expression. In line with this these KO cells showed slower proliferation rates.

In summary, we identified a novel m6A RNA methyltransferase that has a role in overall chromatin organization in human cells. We will present here our newest results.