scholarly journals Ubiquitin-dependent regulation of translesion polymerases

2010 ◽  
Vol 38 (1) ◽  
pp. 110-115 ◽  
Author(s):  
Abel C.S. Chun ◽  
Dong-Yan Jin

In response to DNA damage, TLS (translesion synthesis) allows replicative bypass of various DNA lesions, which stall normal replication. TLS is achieved by low-fidelity polymerases harbouring less stringent active sites. In humans, Y-family polymerases together with Polζ (polymerase ζ) are responsible for TLS across different types of damage. Protein–protein interaction contributes significantly to the regulation of TLS. REV1 plays a central role in TLS because it interacts with all other Y-family members and Polζ. Ubiquitin-dependent regulatory mechanisms also play important roles in TLS. Ubiquitin-binding domains have been found in TLS polymerases and they might be required for TLS activity. Mono-ubiquitination of PCNA (proliferating-cell nuclear antigen), the central scaffold of TLS polymerases, is thought to promote TLS. In addition, both non-proteolytic and proteolytic polyubiquitination of PCNA and TLS polymerases has been demonstrated. Owing to their low fidelity, the recruitment of TLS polymerases is strictly restricted to stalled replication forks.

2005 ◽  
Vol 25 (3) ◽  
pp. 1183-1190 ◽  
Author(s):  
Lajos Haracska ◽  
Narottam Acharya ◽  
Ildiko Unk ◽  
Robert E. Johnson ◽  
Jerard Hurwitz ◽  
...  

ABSTRACT DNA polymerases (Pols) of the Y family rescue stalled replication forks by promoting replication through DNA lesions. Humans have four Y family Pols, η, ι, κ, and Rev1, of which Pols η, ι, and κ have been shown to physically interact with proliferating cell nuclear antigen (PCNA) and be functionally stimulated by it. However, in sharp contrast to the large increase in processivity that PCNA binding imparts to the replicative Pol, Polδ, the processivity of Y family Pols is not enhanced upon PCNA binding. Instead, PCNA binding improves the efficiency of nucleotide incorporation via a reduction in the apparent Km for the nucleotide. Here we show that Polι interacts with PCNA via only one of its conserved PCNA binding motifs, regardless of whether PCNA is bound to DNA or not. The mode of PCNA binding by Polι is quite unlike that in Polδ, where multisite interactions with PCNA provide for a very tight binding of the replicating Pol with PCNA. We discuss the implications of these observations for the accuracy of DNA synthesis during translesion synthesis and for the process of Pol exchange at the lesion site.


2005 ◽  
Vol 289 (3) ◽  
pp. F514-F520 ◽  
Author(s):  
Fang Yu ◽  
Judit Megyesi ◽  
Robert L. Safirstein ◽  
Peter M. Price

The p21 cyclin-dependent kinase (cdk) inhibitor protects cells from cisplatin cytotoxicity in vivo and in vitro. However, the mechanism of protection is not known. Separate p21 domains are known to interact with several different proteins having proapoptotic functions. To investigate the mechanism of protection by p21, we have constructed adenoviruses encoding the different domains of p21. We were able to localize the protective activity to a region of 54 amino acids containing the cyclin-cdk interacting moiety. Other protein binding domains of p21, including the NH2-terminal procaspase-3 interactive region and the COOH-terminal region containing the proliferating cell nuclear antigen binding domain and the nuclear localization signal, had little protective effect on cisplatin cytotoxicity. The dependence of cisplatin cytotoxicity on cdk2 activity was also demonstrated because 1) cisplatin caused a marked increase in cdk2 activity, which was prevented by the p21 expression adenovirus, and 2) a cdk2 dominant-negative adenovirus also protected cells from cisplatin-induced apoptosis. Thus the data suggest that the mechanism of p21 protection is by direct inhibition of cdk2 activity and that cisplatin-induced apoptosis is caused by a cdk2-dependent pathway.


2020 ◽  
Vol 295 (25) ◽  
pp. 8350-8362 ◽  
Author(s):  
Claire Guérillon ◽  
Stine Smedegaard ◽  
Ivo A. Hendriks ◽  
Michael L. Nielsen ◽  
Niels Mailand

Translesion DNA synthesis (TLS) mediated by low-fidelity DNA polymerases is an essential cellular mechanism for bypassing DNA lesions that obstruct DNA replication progression. However, the access of TLS polymerases to the replication machinery must be kept tightly in check to avoid excessive mutagenesis. Recruitment of DNA polymerase η (Pol η) and other Y-family TLS polymerases to damaged DNA relies on proliferating cell nuclear antigen (PCNA) monoubiquitylation and is regulated at several levels. Using a microscopy-based RNAi screen, here we identified an important role of the SUMO modification pathway in limiting Pol η interactions with DNA damage sites in human cells. We found that Pol η undergoes DNA damage- and protein inhibitor of activated STAT 1 (PIAS1)-dependent polySUMOylation upon its association with monoubiquitylated PCNA, rendering it susceptible to extraction from DNA damage sites by SUMO-targeted ubiquitin ligase (STUbL) activity. Using proteomic profiling, we demonstrate that Pol η is targeted for multisite SUMOylation, and that collectively these SUMO modifications are essential for PIAS1- and STUbL-mediated displacement of Pol η from DNA damage sites. These findings suggest that a SUMO-driven feedback inhibition mechanism is an intrinsic feature of TLS-mediated lesion bypass functioning to curtail the interaction of Pol η with PCNA at damaged DNA to prevent harmful mutagenesis.


2018 ◽  
Vol 20 (1) ◽  
pp. 100 ◽  
Author(s):  
Synnøve Ræder ◽  
Anala Nepal ◽  
Karine Bjørås ◽  
Mareike Seelinger ◽  
Rønnaug Kolve ◽  
...  

Proliferating cell nuclear antigen (PCNA) is essential for the organization of DNA replication and the bypass of DNA lesions via translesion synthesis (TLS). TLS is mediated by specialized DNA polymerases, which all interact, directly or indirectly, with PCNA. How interactions between the TLS polymerases and PCNA affects TLS specificity and/or coordination is not fully understood. Here we show that the catalytic subunit of the essential mammalian TLS polymerase POLζ, REV3L, contains a functional AlkB homolog 2 PCNA interacting motif, APIM. APIM from REV3L fused to YFP, and full-length REV3L-YFP colocalizes with PCNA in replication foci. Colocalization of REV3L-YFP with PCNA is strongly reduced when an APIM-CFP construct is overexpressed. We also found that overexpression of full-length REV3L with mutated APIM leads to significantly altered mutation frequencies and mutation spectra, when compared to overexpression of full-length REV3L wild-type (WT) protein in multiple cell lines. Altogether, these data suggest that APIM is a functional PCNA-interacting motif in REV3L, and that the APIM-mediated PCNA interaction is important for the function and specificity of POLζ in TLS. Finally, a PCNA-targeting cell-penetrating peptide, containing APIM, reduced the mutation frequencies and changed the mutation spectra in several cell lines, suggesting that efficient TLS requires coordination mediated by interactions with PCNA.


2008 ◽  
Vol 19 (12) ◽  
pp. 5193-5202 ◽  
Author(s):  
Simone Sabbioneda ◽  
Audrey M. Gourdin ◽  
Catherine M. Green ◽  
Angelika Zotter ◽  
Giuseppina Giglia-Mari ◽  
...  

Y-family DNA polymerases carry out translesion synthesis past damaged DNA. DNA polymerases (pol) η and ι are usually uniformly distributed through the nucleus but accumulate in replication foci during S phase. DNA-damaging treatments result in an increase in S phase cells containing polymerase foci. Using photobleaching techniques, we show that polη is highly mobile in human fibroblasts. Even when localized in replication foci, it is only transiently immobilized. Although ubiquitination of proliferating cell nuclear antigen (PCNA) is not required for the localization of polη in foci, it results in an increased residence time in foci. polι is even more mobile than polη, both when uniformly distributed and when localized in foci. Kinetic modeling suggests that both polη and polι diffuse through the cell but that they are transiently immobilized for ∼150 ms, with a larger proportion of polη than polι immobilized at any time. Treatment of cells with DRAQ5, which results in temporary opening of the chromatin structure, causes a dramatic immobilization of polη but not polι. Our data are consistent with a model in which the polymerases are transiently probing the DNA/chromatin. When DNA is exposed at replication forks, the polymerase residence times increase, and this is further facilitated by the ubiquitination of PCNA.


2003 ◽  
Vol 23 (11) ◽  
pp. 3974-3981 ◽  
Author(s):  
Satoshi Okano ◽  
Li Lan ◽  
Keith W. Caldecott ◽  
Toshio Mori ◽  
Akira Yasui

ABSTRACT DNA single-strand breaks (SSB) are one of the most frequent DNA lesions produced by reactive oxygen species and during DNA metabolism, but the analysis of cellular responses to SSB remains difficult due to the lack of an experimental method to produce SSB alone in cells. By using human cells expressing a foreign UV damage endonuclease (UVDE) and irradiating the cells with UV through tiny pores in membrane filters, we created SSB in restricted areas in the nucleus by the immediate action of UVDE on UV-induced DNA lesions. Cellular responses to the SSB were characterized by using antibodies and fluorescence microscopy. Upon UV irradiation, poly(ADP-ribose) synthesis occurred immediately in the irradiated area. Simultaneously, but dependent on poly(ADP-ribosyl)ation, XRCC1 was translocated from throughout the nucleus, including nucleoli, to the SSB. The BRCT1 domain of XRCC1 protein was indispensable for its poly(ADP-ribose)-dependent recruitment to the SSB. Proliferating cell nuclear antigen and the p150 subunit of chromatin assembly factor 1 also accumulated at the SSB in a detergent-resistant form, which was significantly reduced by inhibition of poly(ADP-ribose) synthesis. Our results show the importance of poly(ADP-ribosyl)ation in sequential cellular responses to SSB.


2014 ◽  
Vol 206 (2) ◽  
pp. 183-197 ◽  
Author(s):  
Michelle K. Zeman ◽  
Jia-Ren Lin ◽  
Raimundo Freire ◽  
Karlene A. Cimprich

Deoxyribonucleic acid (DNA) lesions encountered during replication are often bypassed using DNA damage tolerance (DDT) pathways to avoid prolonged fork stalling and allow for completion of DNA replication. Rad18 is a central E3 ubiquitin ligase in DDT, which exists in a monoubiquitinated (Rad18•Ub) and nonubiquitinated form in human cells. We find that Rad18 is deubiquitinated when cells are treated with methyl methanesulfonate or hydrogen peroxide. The ubiquitinated form of Rad18 does not interact with SNF2 histone linker plant homeodomain RING helicase (SHPRH) or helicase-like transcription factor, two downstream E3 ligases needed to carry out error-free bypass of DNA lesions. Instead, it interacts preferentially with the zinc finger domain of another, nonubiquitinated Rad18 and may inhibit Rad18 function in trans. Ubiquitination also prevents Rad18 from localizing to sites of DNA damage, inducing proliferating cell nuclear antigen monoubiquitination, and suppressing mutagenesis. These data reveal a new role for monoubiquitination in controlling Rad18 function and suggest that damage-specific deubiquitination promotes a switch from Rad18•Ub–Rad18 complexes to the Rad18–SHPRH complexes necessary for error-free lesion bypass in cells.


2008 ◽  
Vol 191 (15) ◽  
pp. 4815-4823 ◽  
Author(s):  
Brenna W. Shurtleff ◽  
Jaylene N. Ollivierre ◽  
Mohammad Tehrani ◽  
Graham C. Walker ◽  
Penny J. Beuning

ABSTRACT Y family DNA polymerases are specialized for replication of damaged DNA and represent a major contribution to cellular resistance to DNA lesions. Although the Y family polymerase active sites have fewer contacts with their DNA substrates than replicative DNA polymerases, Y family polymerases appear to exhibit specificity for certain lesions. Thus, mutation of the steric gate residue of Escherichia coli DinB resulted in the specific loss of lesion bypass activity. We constructed variants of E. coli UmuC with mutations of the steric gate residue Y11 and of residue F10 and determined that strains harboring these variants are hypersensitive to UV light. Moreover, these UmuC variants are dominant negative with respect to sensitivity to UV light. The UV hypersensitivity and the dominant negative phenotype are partially suppressed by additional mutations in the known motifs in UmuC responsible for binding to the β processivity clamp, suggesting that the UmuC steric gate variant exerts its effects via access to the replication fork. Strains expressing the UmuC Y11A variant also exhibit decreased UV mutagenesis. Strikingly, disruption of the dnaQ gene encoding the replicative DNA polymerase proofreading subunit suppressed the dominant negative phenotype of a UmuC steric gate variant. This could be due to a recruitment function of the proofreading subunit or involvement of the proofreading subunit in a futile cycle of base insertion/excision with the UmuC steric gate variant.


2008 ◽  
Vol 364 (1517) ◽  
pp. 621-629 ◽  
Author(s):  
Petra Langerak ◽  
Peter H.L Krijger ◽  
Marinus R Heideman ◽  
Paul C.M van den Berk ◽  
Heinz Jacobs

Proliferating cell nuclear antigen (PCNA) encircles DNA as a ring-shaped homotrimer and, by tethering DNA polymerases to their template, PCNA serves as a critical replication factor. In contrast to high-fidelity DNA polymerases, the activation of low-fidelity translesion synthesis (TLS) DNA polymerases seems to require damage-inducible monoubiquitylation (Ub) of PCNA at lysine residue 164 (PCNA-Ub). TLS polymerases can tolerate DNA damage, i.e. they can replicate across DNA lesions. The lack of proofreading activity, however, renders TLS highly mutagenic. The advantage is that B cells use mutagenic TLS to introduce somatic mutations in immunoglobulin (Ig) genes to generate high-affinity antibodies. Given the critical role of PCNA-Ub in activating TLS and the role of TLS in establishing somatic mutations in immunoglobulin genes, we analysed the mutation spectrum of somatically mutated immunoglobulin genes in B cells from PCNA K164R knock-in mice. A 10-fold reduction in A/T mutations is associated with a compensatory increase in G/C mutations—a phenotype similar to Polη and mismatch repair-deficient B cells. Mismatch recognition, PCNA-Ub and Polη probably act within one pathway to establish the majority of mutations at template A/T. Equally relevant, the G/C mutator(s) seems largely independent of PCNA K164 modification.


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