Ribonucleotide reductase from Fusarium oxysporum does not Respond to DNA replication stress

Rotem Cohen; Shira Milo; Sushma Sharma; Alon Savidor; Shay Covo

doi:10.1016/j.dnarep.2019.102674

Ribonucleotide reductase from Fusarium oxysporum does not Respond to DNA replication stress

DNA Repair (Amst). 2019 Nov:83:102674. doi: 10.1016/j.dnarep.2019.102674. Epub 2019 Jul 24.

Authors

Rotem Cohen¹, Shira Milo¹, Sushma Sharma², Alon Savidor³, Shay Covo⁴

Affiliations

¹ Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot, 76100, Israel.
² Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden.
³ de Botton Institute for Protein Profiling, the Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot, 76100, Israel.
⁴ Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University, Rehovot, 76100, Israel. Electronic address: shay.covo@mail.huji.ac.il.

PMID: 31375409
DOI: 10.1016/j.dnarep.2019.102674

Abstract

Ribonucleotide reductase (RNR) catalyzes the rate limiting step in dNTP biosynthesis and is tightly regulated at the transcription and activity levels. One of the best characterized responses of yeast to DNA damage is up-regulation of RNR transcription and activity and consequently, elevation of the dNTP pools. Hydroxyurea is a universal inhibitor of RNR that causes S phase arrest. It is used in the clinic to treat certain types of cancers. Here we studied the response of the fungal plant pathogen Fusarium oxysporum to hydroxyurea in order to generate hypotheses that can be used in the future in development of a new class of pesticides. F. oxysporum causes severe damage to more than 100 agricultural crops and specifically threatens banana cultivation world-wide. Although the recovery of F. oxysporum from transient hydroxyurea exposure was similar to the one of Saccharomyces cerevisiae, colony formation was strongly inhibited in F. oxysporum in comparison with S. cerevisiae. As expected, genomic and phosphoproteomic analyses of F. oxysporum conidia (spores) exposed to hydroxyurea showed hallmarks of DNA replication perturbation and activation of recombination. Unexpectedly and strikingly, RNR was not induced by either hydroxyurea or the DNA-damaging agent methyl methanesulfonate as determined at the RNA and protein levels. Consequently, dNTP concentrations were significantly reduced, even in response to a low dose of hydroxyurea. Methyl methanesulfonate treatment did not induce dNTP pools in F. oxysporum, in contrast to the response of RNR and dNTP pools to DNA damage and hydroxyurea in several tested organisms. Our results are important because the lack of a feedback mechanism to increase RNR expression in F. oxysporum is expected to sensitize the pathogen to a fungal-specific ribonucleotide inhibitor. The potential impact of our observations on F. oxysporum genome stability and genome evolution is discussed.

Keywords: Fusarium oxysporum; Ribonucleotide reductase.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

DNA Damage* / genetics
DNA Replication / drug effects
DNA Replication / genetics*
Fusarium / drug effects
Fusarium / enzymology*
Fusarium / genetics*
Ribonucleotide Reductases / metabolism*
Urea / pharmacology

Substances

Urea
Ribonucleotide Reductases