scholarly journals A hyperactive variant of theEscherichia colianaerobic transcription factor FNR enhances ionizing radiation resistance

2018 ◽  
Author(s):  
Steven T. Bruckbauer ◽  
Joseph D. Trimarco ◽  
Elizabeth A. Wood ◽  
John R. Battista ◽  
Michael M. Cox

AbstractWe have previously generated four replicate populations of ionizing radiation (IR)- resistantEscherichia colithough directed evolution. Sequencing of isolates from these populations revealed that mutations affecting DNA repair (through DNA double-strand break repair and replication restart), ROS amelioration, and cell wall metabolism were prominent. Three mutations involved in DNA repair explained the IR resistance phenotype in one population, and similar DNA repair mutations were prominent in two others. The remaining population, IR-3-20, had no mutations in the key DNA repair proteins, suggesting that it had taken a different evolutionary path to IR resistance. Here, we present evidence that a variant of the anaerobic metabolism transcription factor FNR isolated from population IR-3-20 can play a role in IR resistance. An FNR variant is unique to IR-3-20 and suggests a role for altered global metabolism through the FNR regulon as a means for experimentally-evolved IR resistance.

2021 ◽  
pp. jcs.247809
Author(s):  
Annika Pfeiffer ◽  
Laura K. Herzog ◽  
Martijn S. Luijsterburg ◽  
Rashmi G. Shah ◽  
Magdalena B. Rother ◽  
...  

DNA damage-induced SUMOylation serves as a signal for two antagonizing proteins that both stimulate repair of DNA double strand breaks (DSBs). Here, we demonstrate that the SUMO-dependent recruitment of the deubiquitylating enzyme ataxin-3 to DSBs, unlike recruitment of the ubiquitin ligase RNF4, additionally depends on PARP1-mediated poly(ADP-ribosyl)ation (PARylation). The co-dependence of ataxin-3 recruitment on PARylation and SUMOylation temporally confines its presence at DSBs to a short time window directly following detection of the DNA damage. We propose that this mechanism ensures that ataxin-3 prevents the premature removal of DNA repair proteins only during the early phase of the DSB response and does not interfere with the subsequent timely displacement of DNA repair proteins by RNF4. Thus, our data show that PARylation differentially regulates SUMO-dependent recruitment of ataxin-3 and RNF4 to DSBs, explaining how both proteins can play a stimulatory role at DSBs despite their opposing activities.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Maria Nowacka-Zawisza ◽  
Agata Raszkiewicz ◽  
Tomasz Kwasiborski ◽  
Ewa Forma ◽  
Magdalena Bryś ◽  
...  

Genetic polymorphisms in DNA repair genes may affect DNA repair efficiency and may contribute to the risk of developing cancer. The aim of our study was to investigate single nucleotide polymorphisms (SNPs) in RAD51 (rs2619679, rs2928140, and rs5030789) and XRCC3 (rs1799796) involved in DNA double-strand break repair and their relationship to prostate cancer. The study group included 99 men diagnosed with prostate cancer and 205 cancer-free controls. SNP genotyping was performed using the PCR-RFLP method. A significant association was detected between RAD51 rs5030789 polymorphism and XRCC3 rs1799796 polymorphism and an increased risk of prostate cancer. Our results indicate that RAD51 and XRCC3 polymorphism may contribute to prostate cancer.


Cancers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1617
Author(s):  
Barbara N. Borsos ◽  
Hajnalka Majoros ◽  
Tibor Pankotai

The proper function of DNA repair is indispensable for eukaryotic cells since accumulation of DNA damages leads to genome instability and is a major cause of oncogenesis. Ubiquitylation and deubiquitylation play a pivotal role in the precise regulation of DNA repair pathways by coordinating the recruitment and removal of repair proteins at the damaged site. Here, we summarize the most important post-translational modifications (PTMs) involved in DNA double-strand break repair. Although we highlight the most relevant PTMs, we focus principally on ubiquitylation-related processes since these are the most robust regulatory pathways among those of DNA repair.


PLoS ONE ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. e0199482 ◽  
Author(s):  
Steven T. Bruckbauer ◽  
Joseph D. Trimarco ◽  
Camille Henry ◽  
Elizabeth A. Wood ◽  
John R. Battista ◽  
...  

2008 ◽  
Vol 28 (11) ◽  
pp. 3639-3651 ◽  
Author(s):  
Yufuko Akamatsu ◽  
Yasuto Murayama ◽  
Takatomi Yamada ◽  
Tomofumi Nakazaki ◽  
Yasuhiro Tsutsui ◽  
...  

ABSTRACT The Schizosaccharomyces pombe nip1 +/ctp1 + gene was previously identified as an slr (synthetically lethal with rad2) mutant. Epistasis analysis indicated that Nip1/Ctp1 functions in Rhp51-dependent recombinational repair, together with the Rad32 (spMre11)-Rad50-Nbs1 complex, which plays important roles in the early steps of DNA double-strand break repair. Nip1/Ctp1 was phosphorylated in asynchronous, exponentially growing cells and further phosphorylated in response to bleomycin treatment. Overproduction of Nip1/Ctp1 suppressed the DNA repair defect of an nbs1-s10 mutant, which carries a mutation in the FHA phosphopeptide-binding domain of Nbs1, but not of an nbs1 null mutant. Meiotic DNA double-strand breaks accumulated in the nip1/ctp1 mutant. The DNA repair phenotypes and epistasis relationships of nip1/ctp1 are very similar to those of the Saccharomyces cerevisiae sae2/com1 mutant, suggesting that Nip1/Ctp1 is a functional homologue of Sae2/Com1, although the sequence similarity between the proteins is limited to the C-terminal region containing the RHR motif. We found that the RxxL and CxxC motifs are conserved in Schizosaccharomyces species and in vertebrate CtIP, originally identified as a cofactor of the transcriptional corepressor CtBP. However, these two motifs are not found in other fungi, including Saccharomyces and Aspergillus species. We propose that Nip1/Ctp1 is a functional counterpart of Sae2/Com1 and CtIP.


2019 ◽  
Vol 116 (28) ◽  
pp. 14174-14180 ◽  
Author(s):  
Ameer L. Elaimy ◽  
John J. Amante ◽  
Lihua Julie Zhu ◽  
Mengdie Wang ◽  
Charlotte S. Walmsley ◽  
...  

Vascular endothelial growth factor (VEGF) signaling in tumor cells mediated by neuropilins (NRPs) contributes to the aggressive nature of several cancers, including triple-negative breast cancer (TNBC), independently of its role in angiogenesis. Understanding the mechanisms by which VEGF–NRP signaling contributes to the phenotype of such cancers is a significant and timely problem. We report that VEGF–NRP2 promote homologous recombination (HR) in BRCA1 wild-type TNBC cells by contributing to the expression and function of Rad51, an essential enzyme in the HR pathway that mediates efficient DNA double-strand break repair. Mechanistically, we provide evidence that VEGF–NRP2 stimulates YAP/TAZ-dependent Rad51 expression and that Rad51 is a direct YAP/TAZ–TEAD transcriptional target. We also discovered that VEGF–NRP2–YAP/TAZ signaling contributes to the resistance of TNBC cells to cisplatin and that Rad51 rescues the defects in DNA repair upon inhibition of either VEGF–NRP2 or YAP/TAZ. These findings reveal roles for VEGF–NRP2 and YAP/TAZ in DNA repair, and they indicate a unified mechanism involving VEGF–NRP2, YAP/TAZ, and Rad51 that contributes to resistance to platinum chemotherapy.


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