DNA repair enzymes of the Antarctic Dry Valley metagenome

Elizabeth Rzoska-Smith; Ronja Stelzer; Maria Monterio; Stephen C Cary; Adele Williamson

doi:10.3389/fmicb.2023.1156817

DNA repair enzymes of the Antarctic Dry Valley metagenome

Front Microbiol. 2023 Apr 14:14:1156817. doi: 10.3389/fmicb.2023.1156817. eCollection 2023.

Authors

Elizabeth Rzoska-Smith¹, Ronja Stelzer¹, Maria Monterio², Stephen C Cary², Adele Williamson¹

Affiliations

¹ Proteins and Microbes Laboratory, School of Science, University of Waikato, Hamilton, New Zealand.
² Thermophile Research Unit, School of Science, University of Waikato, Hamilton, New Zealand.

Abstract

Microbiota inhabiting the Dry Valleys of Antarctica are subjected to multiple stressors that can damage deoxyribonucleic acid (DNA) such as desiccation, high ultraviolet light (UV) and multiple freeze-thaw cycles. To identify novel or highly-divergent DNA-processing enzymes that may enable effective DNA repair, we have sequenced metagenomes from 30 sample-sites which are part of the most extensive Antarctic biodiversity survey undertaken to date. We then used these to construct wide-ranging sequence similarity networks from protein-coding sequences and identified candidate genes involved in specialized repair processes including unique nucleases as well as a diverse range of adenosine triphosphate (ATP) -dependent DNA ligases implicated in stationary-phase DNA repair processes. In one of the first direct investigations of enzyme function from these unique samples, we have heterologously expressed and assayed a number of these enzymes, providing insight into the mechanisms that may enable resident microbes to survive these threats to their genomic integrity.

Keywords: Antarctic Dry Valleys; DNA ligase; DNA repair; metagenome; nuclease; sequence similarity network.