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bioRxiv · 10.1101/2024.04.02.587769

DTX3L ubiquitin ligase ubiquitinates single-stranded nucleic acids

Dearlove, E. L.·Chatrin, C.·Buetow, L.·Ahmed, S. F.·Schmidt, T.·Bushell, M.·Smith, B. O.·Huang, D. T.
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Abstract

Ubiquitination typically involves covalent linking of ubiquitin (Ub) to a lysine residue on a protein substrate. Recently, new facets of this process have emerged, including Ub modification of non-proteinaceous substrates like ADP-ribose by the DELTEX E3 ligase family. Here we show that the DELTEX family member DTX3L expands this non-proteinaceous substrate repertoire to include single-stranded DNA and RNA. Although the N-terminal region of DTX3L contains single-stranded nucleic acid binding domains and motifs, the minimal catalytically competent fragment comprises the C-terminal RING and DTC domains (RD). DTX3L-RD catalyses ubiquitination of the 3-end of single-stranded DNA and RNA, as well as double-stranded DNA with a 3 overhang of two or more nucleotides. This modification is reversibly cleaved by deubiquitinases. NMR and biochemical analyses reveal that the DTC domain binds single-stranded DNA and facilitates the catalysis of Ub transfer from RING-bound E2-conjugated Ub. Our study unveils the direct ubiquitination of nucleic acids by DTX3L, laying the groundwork for understanding its functional implications.

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Dearlove, E. L., Chatrin, C., Buetow, L., Ahmed, S. F., Schmidt, T., Bushell, M., Smith, B. O., Huang, D. T.. 2024-04-02. DTX3L ubiquitin ligase ubiquitinates single-stranded nucleic acids. https://doi.org/10.1101/2024.04.02.587769

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