Elsevier

DNA Repair

Volume 125, May 2023, 103484
DNA Repair

A novel role for Mms2 in the control of spontaneous mutagenesis and Pol3 abundance

https://doi.org/10.1016/j.dnarep.2023.103484Get rights and content
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Highlights

  • The abundance of Pol3, the catalytic subunit of DNA polymerase δ depends on Mms2.

  • Increased cellular abundance of Mms2 leads to a spontaneous mutator effect.

  • The promutagenic activity of Mms2 is Ubc13-independent.

  • Mms2-induced mutagenesis requires Ubc4, Rsp5 and Not4 ubiquitinating enzymes

  • Mms2-induced mutagenesis depends on four-subunit polymerase zeta and Rev1

Abstract

Mms2 is a ubiquitin E2-variant protein with a very well-documented function in the tolerance pathway that protects both human and yeast cells from the lethal and mutagenic effects of DNA damage. Interestingly, a high expression level of human MMS2 is associated with poor survival prognosis in different cancer diseases. Here we have analyzed the physiological effects of Mms2 overproduction in yeast cells. We show that an increased level of this protein causes a spontaneous mutator effect independent of Ubc13, a cognate partner of Mms2 in the PCNA-polyubiquitinating complex responsible for the template switch. Instead, this new promutagenic role of Mms2 requires Ubc4 (E2) and two ubiquitin ligases of HECT and RING families, Rsp5 and Not4, respectively. We have established that the promutagenic activity of Mms2 is dependent on the activities of error-prone DNA polymerase ζ and Rev1. Additionally, it requires the ubiquitination of K164 in PCNA which facilitates recruitment of these translesion polymerases to the replication complex. Importantly, we have established also that the cellular abundance of Mms2 influences the cellular level of Pol3, the catalytic subunit of replicative DNA polymerase δ. Lack of Mms2 increases the Pol3 abundance, whereas in response to Mms2 overproduction the Pol3 level decreases. We hypothesize that increased levels of spontaneous mutagenesis may result from the Mms2-induced reduction in Pol3 accumulation leading to increased participation of error-prone polymerase ζ in the replication complex

Keywords

Spontaneous mutagenesis
Mms2
Pol3
DNA polymerase zeta
DNA polymerase delta
S. cerevisiae

Data availability

No data was used for the research described in the article.

Cited by (0)

1

Current address: Genome Stability Research Group, Institute of Enzymology Research Centre for Natural Sciences, 1117 Budapest, Hungary.