RNA m6A methylation regulates the ultraviolet-induced DNA damage response

Abstract

Cell proliferation and survival require the faithful maintenance and propagation of genetic information, which are threatened by the ubiquitous sources of DNA damage present intracellularly and in the external environment. A system of DNA repair, called the DNA damage response (DDR), detects and repairs damaged DNA and prevents cell division until the repair is complete. Here we report that methylation at the 6 position of adenosine (m6A) in RNA is rapidly (within 2 minutes) and transiently induced at DNA damage sites in response to UV. This modification occurs on numerous poly(A)+ transcripts and is regulated by the methyltransferase METTL31 and the demethylase FTO2. In the absence of METTL3 catalytic activity, cells showed delayed repair of UV-induced cyclobutane pyrimidine (CPD) adducts and elevated sensitivity to UV, demonstrating the importance of m6A in the UV-responsive DDR. Multiple DNA polymerases are involved in the UV response, some of which resynthesize DNA after the lesion has been excised by the nucleotide excision repair (NER) pathway3, while others participate in trans-lesion synthesis (TLS) to allow replication past damaged lesions in S phase4. DNA polymerase κ (Pol κ), which has been implicated in both NER and TLS5,6, required the catalytic activity of METTL3 for immediate localization to UV-induced DNA damage sites. Importantly, Pol κ over-expression qualitatively suppressed the CPD removal defect associated with METTL3 loss. Taken together, we have uncovered a novel function for RNA m6A modification in the UV-induced DDR, and our findings collectively support a model whereby m6A RNA serves as a beacon for the selective, rapid recruitment of Pol κ to damage sites to facilitate repair and cell survival.

RNA m6A modification and its function in diseases

“…Minimal differences were noted on the content and the location of m 6 A in cytoplasmic mRNA and chromatin-associated nascent pre-mRNA or nucleoplasmic mRNA at steady-state [16], suggesting that m 6 A methylation occurred co-transcriptionally. This idea was supported by recent studies that METTL3 interacted with chromatin and the transcription machinery [17][18][19].…”

“…Zhou et al [44] demonstrated that the nuclear localization of YTHDF2 induced by heat shock stress could prevent the m 6 A in the 5′-UTR of stress-induced transcripts from demethylation by FTO. Moreover, Xiang et al showed that in response to ultraviolet-induced DNA damage, METTL3/METTL14 was recruited to damaged sites to install m 6 A on RNAs that can be removed by FTO in nucleus [19]. Hence, m 6 A demethylation could occur both in the nucleus and cytoplasm with substantial functional outcomes.…”

“…This study was first to indicate that the ubiquitously distributed m 6 A modifications on mRNA might be reversely regulated by methyltransferases and demethylases, thereby serving as a previously unappreciated layer of regulation on mRNAs. Furthermore, FTO-mediated m 6 A demethylation was involved in adipogenesis [32][33][34], acute myeloid leukemia (AML) cell transformation, leukemogenesis [35,36], and ultravioletinduced DNA damage response [19], emphasizing the importance of m 6 A modification in different cell contexts. Although FTO catalyzed the demethylation of m 6 A residues both in vitro and in vivo [6,37], FTO was instead the genuine demethylase of m 6 Am, which was highly similar to m 6 A and enriched in the 5′-UTR adjacent to the N 7 -methylguanosine (m 7 G) cap [38].…”

Entwicklung einer DNA‐Polymerase für die direkte m6A‐Sequenzierung

“…N 6 -Methyladenosin (m 6 A) wurde als Zielmodifikation ausgewählt, da es sich hierbei um eine reversible [6] und häu-fige [7] Modifikation in der mRNAv on Säugetieren handelt. m 6 Ab eeinflusst mRNA-Spleißen, [8] mRNA-Export aus dem Zellkern, [6b, 9] Tr anslation [10] und mRNA-Abbau.[11] Erwartete Funktionen umfassen die Synchronisation der Tr anslation, [12] die Kontrolle des zirkadianen Rhythmus, [9] die Initiation der DNA-Reparatur [13] und den Abbau von materner RNA [14] …”

“…[11] Erwartete Funktionen umfassen die Synchronisation der Tr anslation, [12] die Kontrolle des zirkadianen Rhythmus, [9] die Initiation der DNA-Reparatur [13] und den Abbau von materner RNA [14] …”