Ubiquitylation of nucleic acids by DELTEX ubiquitin E3 ligase DTX3L

Recent discoveries expanding the spectrum of ubiquitylation substrates to include non-proteinaceous molecules have broadened our understanding of this modification beyond conventional protein targets. However, the existence of additional types of substrates remains elusive. Here, we present evidence that nucleic acids can also be directly ubiquitylated. DTX3L, a member of the DELTEX family E3 ubiquitin ligases, ubiquitylates DNA and RNA in vitro and that this activity is not shared with another DELTEX family member DTX2. DTX3L shows preference for the 3’-terminal adenosine over other nucleotides. In addition, we demonstrate that ubiquitylation of nucleic acids is reversible by DUBs such as USP2 and SARS-CoV-2 PLpro. Overall, our study provides evidence for reversible ubiquitylation of nucleic acids in vitro and discusses its potential functional implications.