Eukaryotic stress–induced mutagenesis is limited by a local control of translesion synthesis

Abstract

The DNA damage response (DDR) preserves the genetic integrity of the cell by sensing and repairing damages after a genotoxic stress. Translesion Synthesis (TLS), an error-prone DNA damage tolerance pathway, is controlled by PCNA ubiquitination. In this work, we raise the question whether TLS is controlled locally or globally. Using a recently developed method that allows to follow the bypass of a single lesion inserted into the yeast genome, we show that (i) TLS is controlled locally at each individual lesion by PCNA ubiquitination, (ii) a single lesion is enough to induce PCNA ubiquitination and (iii) PCNA ubiquitination is imperative for TLS to occur. More importantly, we show that the activation of the DDR that follows a genotoxic stress does not increase TLS at individual lesions. We conclude that unlike the SOS response in bacteria, the eukaryotic DDR does not promote TLS and mutagenesis.

Opposite roles of Rad5 in DNA damage tolerance: playing in both error-free and mutagenic lesion bypass

“…The mutation affecting Ubc13-binding ( RAD5IA ubi ) led to a strong increase in TLS at both (6-4)TT photoproduct and N2dG-AAF lesions (Figure 2A and B). This increase in TLS is similar to the one previously observed in the absence of ubc13 [21,22]. As shown in Figure 4, RAD5IA ubi shows a high sensitivity to a more global genotoxic stress such as 4NQO (4-Nitroquinoline-1-oxide) treatment, similar to the ubc13Δ strain.…”

“…As we have shown previously, TLS bypass of the (6-4)TT photoproduct relies almost exclusively on the TLS polymerases Rev1 and Pol ζ [21,22]. The bypass of N2dG-AAF lesion is mostly dependent on Rev1 and Pol ζ, while a small part can be performed by pol h [22]. The RAD5 allele unable to bind Rev1 ( RAD5FN Rev1 ) causes a severe decrease in the level of TLS at both (6-4)TT photoproduct and N2dG-AAF lesions (Figure 2A and B).…”

“…As we have shown previously, TLS bypass of the (6-4)TT photoproduct relies almost exclusively on the TLS polymerases Rev1 and Pol ζ [21,22]. The bypass of N2dG-AAF lesion is mostly dependent on Rev1 and Pol ζ, while a small part can be performed by pol h [22].…”

“…We observed a significant decrease in TLS for the N2dG-AAF lesions, and a very moderate decrease for the TT(6-4) photoproduct compared to the parental strain. It is important to note that in the rad5 Δ strain, no polyubiquitination of PCNA occurs: we could therefore expect in these strains a strong increase of TLS as observed in the ubc13 Δ, RAD5IA ubi , or RAD5DE ubi-helic mutants [21,22]. However, due to the absence of Rad5 and its function of recruiting Rev1, TLS does not increase in this strain.…”

MicroRNA‐215‐5p promotes proliferation, invasion, and inhibits apoptosis in liposarcoma cells by targeting MDM2

“…High PCNA expression is associated with active cell proliferation 48 and upregulation of miR-215-5p was found to promote PCNA expression in this study, which suggests that upregulation of miR-215-5p expression in LPS can promote cell proliferation. Bcl-2 49 is an oncogene that inhibits apoptosis, 50 caspase-3 51 is an important terminal cleaving enzyme in the process of apoptosis and Bax is one of the important pro-apoptotic genes.…”