Centre for Research on Biomolecular Interactions presents Dr. Michael Musheev, Institute of Molecular Biology at Johannes Gutenberg University Mainz
TALK: THE ORIGIN OF GENOMIC N6-METHYL-DEOXYADENOSINE IN
MAMMALIAN CELLS
Abstract: DNA adenine methylation (N6-methyl-deoxyadenosine, m6dA) was recently proposed as a novel, heritable epigenetic mark in mammals. However, the origin and biological relevance of mammalian genomic m6dA is controversial, and a mammalian “DNA (adenine-N6)-methyltransferase” remains elusive. Using isotopic labeling coupled to ultrasensitive mass-spectrometry analysis, I will show that m6dA occurs in mammalian genomic DNA, albeit at very low levels of 900-2,500 molecules per genome. In my talk, I will also provide strong evidence that DNA adenine methylation is not the product of a DNA (adenine-N6)-methyltransferase. Instead, I will demonstrate that genomic m6dA originates from free ribo-m6A (N6-methyladenosine), a breakdown product of methylated RNA. Ribo-m6A is metabolized to m6dA and mis-incorporated into DNA during replication. The results reveal the new metabolic pathway and argue against m6dA acting as a heritable, epigenetic DNA mark in mammalian cells.
Date: Wednesday November 11,2020
Time:2:00pm-3:00pm
