
==== Front
bioRxiv
BIORXIV
bioRxiv
2692-8205
Cold Spring Harbor Laboratory

10.1101/2024.08.27.609911
preprint
1
Article
A non-tethering role for the Drosophila Pol θ linker domain in promoting damage resolution
Blanch Justin R. http://orcid.org/0000-0002-9939-7700

Krishnamurthy Manan http://orcid.org/0000-0001-8906-0533

McVey Mitch http://orcid.org/0000-0001-8883-0188

27 8 2024
2024.08.27.609911https://creativecommons.org/licenses/by-nc-nd/4.0/ This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which allows reusers to copy and distribute the material in any medium or format in unadapted form only, for noncommercial purposes only, and only so long as attribution is given to the creator.
http://biorxiv.org/lookup/doi/10.1101/2024.08.27.609911
nihpp-2024.08.27.609911.pdf
Abstract

DNA polymerase theta (Pol θ) is an error-prone translesion polymerase that becomes crucial for DNA double-strand break repair when cells are deficient in homologous recombination or non-homologous end joining. In some organisms, Pol θ also promotes tolerance of DNA interstrand crosslinks. Due to its importance in DNA damage tolerance, Pol θ is an emerging target for treatment of cancer and disease. Prior work has characterized the functions of the Pol θ helicase-like and polymerase domains, but the roles of the linker domain are largely unknown. Here, we show that the Drosophila melanogaster Pol θ linker domain promotes egg development and is required for tolerance of DNA double-strand breaks and interstrand crosslinks. While a linker domain with scrambled amino acid residues is sufficient for DNA repair, replacement of the linker with part of the Homo sapiens Pol θ linker or a disordered region from the FUS RNA-binding protein does not restore function. These results demonstrate that the linker domain is not simply a random tether between the helicase-like and polymerase domains. Furthermore, they suggest that intrinsic amino acid residue properties, rather than protein interaction motifs, are more critical for Pol θ linker functions in DNA repair.
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