Identification of a Topoisomerase I Mutant, scsA1, as an Extragenic Suppressor of a Mutation in scaANBS1, the Apparent Homolog of Human Nibrin in Aspergillus nidulans

Genetics ◽  
2003 ◽  
Vol 164 (3) ◽  
pp. 935-945 ◽  
Author(s):  
Marcia R Z Kress Fagundes ◽  
Larissa Fernandes ◽  
Marcela Savoldi ◽  
Steven D Harris ◽  
Maria H S Goldman ◽  
...  
Keyword(s):  
Dna Damage ◽  
Aspergillus Nidulans ◽  
Topoisomerase I ◽  
Cell Cycle Checkpoint ◽  
Dna Double Strand Breaks ◽  
Dna Damaging Agents ◽  
Cycle Checkpoint ◽  
Increased Sensitivity ◽  
Cellular Dna ◽  
Extragenic Suppressors

Abstract The Mre11-Rad50-Nbs1 protein complex has emerged as a central player in the human cellular DNA damage response, and recent observations suggest that these proteins are at least partially responsible for the linking of DNA damage detection to DNA repair and cell cycle checkpoint functions. Mutations in scaANBS1, which encodes the apparent homolog of human nibrin in Aspergillus nidulans, inhibit growth in the presence of the antitopoisomerase I drug camptothecin. This article describes the selection and characterization of extragenic suppressors of the scaA1 mutation, with the aim of identifying other proteins that interfere with the pathway or complex in which the ScaA would normally be involved. Fifteen extragenic suppressors of the scaA1 mutation were isolated. The topoisomerase I gene can complement one of these suppressors. Synergistic interaction between the scaANBS1 and scsATOP1 genes in the presence of DNA-damaging agents was observed. Overexpression of topoisomerase I in the scaA1 mutant causes increased sensitivity to DNA-damaging agents. The scsATOP1 and the scaANBS1 gene products could functionally interact in pathways that either monitor or repair DNA double-strand breaks.

scholarly journals Dual-utility NLS drives RNF169-dependent DNA damage responses

2017 ◽  
Vol 114 (14) ◽  
pp. E2872-E2881 ◽  
Author(s):  
Liwei An ◽  
Yiyang Jiang ◽  
Howin H. W. Ng ◽  
Ellen P. S. Man ◽  
Jie Chen ◽  
...  
Keyword(s):  
Dna Damage ◽  
Ring Finger ◽  
Direct Interaction ◽  
Cell Cycle Checkpoint ◽  
High Fidelity ◽  
Dna Double Strand Breaks ◽  
Receptor Associated Protein ◽  
Cycle Checkpoint ◽  
Specific Protease ◽  
Localization Signal

Loading of p53-binding protein 1 (53BP1) and receptor-associated protein 80 (RAP80) at DNA double-strand breaks (DSBs) drives cell cycle checkpoint activation but is counterproductive to high-fidelity DNA repair. ring finger protein 169 (RNF169) maintains the balance by limiting the deposition of DNA damage mediator proteins at the damaged chromatin. We report here that this attribute is accomplished, in part, by a predicted nuclear localization signal (NLS) that not only shuttles RNF169 into the nucleus but also promotes its stability by mediating a direct interaction with the ubiquitin-specific protease USP7. Guided by the crystal structure of USP7 in complex with the RNF169 NLS, we uncoupled USP7 binding from its nuclear import function and showed that perturbing the USP7–RNF169 complex destabilized RNF169, compromised high-fidelity DSB repair, and hypersensitized cells to poly (ADP-ribose) polymerase inhibition. Finally, expression of USP7 and RNF169 positively correlated in breast cancer specimens. Collectively, our findings uncover an NLS-mediated bipartite mechanism that supports the nuclear function of a DSB response protein.

scholarly journals FANCJ compensates for RAP80 deficiency and suppresses genomic instability induced by interstrand cross-links

2020 ◽  
Vol 48 (16) ◽  
pp. 9161-9180 ◽  
Author(s):  
Sanket Awate ◽  
Joshua A Sommers ◽  
Arindam Datta ◽  
Sumeet Nayak ◽  
Marina A Bellani ◽  
...  
Keyword(s):  
Dna Damage ◽  
Chromosomal Instability ◽  
Dna Helicase ◽  
Cell Cycle Checkpoint ◽  
Dna Double Strand Breaks ◽  
Compensatory Mechanisms ◽  
Critical Function ◽  
Interstrand Cross Links ◽  
Cycle Checkpoint ◽  
Diploid Cells

Abstract FANCJ, a DNA helicase and interacting partner of the tumor suppressor BRCA1, is crucial for the repair of DNA interstrand crosslinks (ICL), a highly toxic lesion that leads to chromosomal instability and perturbs normal transcription. In diploid cells, FANCJ is believed to operate in homologous recombination (HR) repair of DNA double-strand breaks (DSB); however, its precise role and molecular mechanism is poorly understood. Moreover, compensatory mechanisms of ICL resistance when FANCJ is deficient have not been explored. In this work, we conducted a siRNA screen to identify genes of the DNA damage response/DNA repair regime that when acutely depleted sensitize FANCJ CRISPR knockout cells to a low concentration of the DNA cross-linking agent mitomycin C (MMC). One of the top hits from the screen was RAP80, a protein that recruits repair machinery to broken DNA ends and regulates DNA end-processing. Concomitant loss of FANCJ and RAP80 not only accentuates DNA damage levels in human cells but also adversely affects the cell cycle checkpoint, resulting in profound chromosomal instability. Genetic complementation experiments demonstrated that both FANCJ’s catalytic activity and interaction with BRCA1 are important for ICL resistance when RAP80 is deficient. The elevated RPA and RAD51 foci in cells co-deficient of FANCJ and RAP80 exposed to MMC are attributed to single-stranded DNA created by Mre11 and CtIP nucleases. Altogether, our cell-based findings together with biochemical studies suggest a critical function of FANCJ to suppress incompletely processed and toxic joint DNA molecules during repair of ICL-induced DNA damage.

scholarly journals Aspergillus nidulans uvsBATR and scaANBS1 Genes Show Genetic Interactions during Recovery from Replication Stress and DNA Damage

2005 ◽  
Vol 4 (7) ◽  
pp. 1239-1252 ◽  
Author(s):  
Marcia Regina von Zeska Kress Fagundes ◽  
Camile P. Semighini ◽  
Iran Malavazi ◽  
Marcela Savoldi ◽  
Joel Fernandes de Lima ◽  
...  
Keyword(s):  
Dna Damage ◽  
Aspergillus Nidulans ◽  
Replication Stress ◽  
Genetic Interactions ◽  
Dna Double Strand Breaks ◽  
Focus Formation ◽  
Strand Breaks ◽  
Mre11 Complex ◽  
Cellular Dna ◽  
Atr Kinases

ABSTRACT The ATM/ATR kinases and the Mre11 (Mre11-Rad50-Nbs1) protein complex are central players in the cellular DNA damage response. Here we characterize possible interactions between Aspergillus nidulans uvsB ATR and the Mre11 complex (scaA NBS1). We demonstrate that there is an epistatic relationship between uvsB ATR, the homolog of the ATR/MEC1 gene, and scaA NBS1, the homolog of the NBS1/XRS2 gene, for both repair and checkpoint functions and that correct ScaANBS1 expression during recovery from replication stress depends on uvsB ATR. In addition, we also show that the formation of UvsC foci during recovery from replication stress is dependent on both uvsB ATR and scaA NBS1 function. Furthermore, ScaANBS1 is also dependent on uvsB ATR for nuclear focus formation upon the induction of DNA double-strand breaks by phleomycin. Our results highlight the extensive genetic interactions between UvsB and the Mre11 complex that are required for S-phase progression and recovery from DNA damage.

scholarly journals Actin-Related Protein 6 (Arp6) Influences Double-Strand Break Repair in Yeast

2021 ◽  
Vol 1 (2) ◽  
pp. 225-238
Author(s):  
Mohsen Hooshyar ◽  
Daniel Burnside ◽  
Maryam Hajikarimlou ◽  
Katayoun Omidi ◽  
Alexander Jesso ◽  
...  
Keyword(s):  
Dna Damage ◽  
Chromatin Remodeling ◽  
Genetic Interaction ◽  
Interaction Analysis ◽  
Strand Break ◽  
Dna Double Strand Breaks ◽  
Dsb Repair ◽  
Dna Damaging Agents ◽  
Repair Efficiency ◽  
Chromosomal Breaks

DNA double-strand breaks (DSBs) are the most deleterious form of DNA damage and are repaired through non-homologous end-joining (NHEJ) or homologous recombination (HR). Repair initiation, regulation and communication with signaling pathways require several histone-modifying and chromatin-remodeling complexes. In budding yeast, this involves three primary complexes: INO80-C, which is primarily associated with HR, SWR1-C, which promotes NHEJ, and RSC-C, which is involved in both pathways as well as the general DNA damage response. Here we identify ARP6 as a factor involved in DSB repair through an RSC-C-related pathway. The loss of ARP6 significantly reduces the NHEJ repair efficiency of linearized plasmids with cohesive ends, impairs the repair of chromosomal breaks, and sensitizes cells to DNA-damaging agents. Genetic interaction analysis indicates that ARP6, MRE11 and RSC-C function within the same pathway, and the overexpression of ARP6 rescues rsc2∆ and mre11∆ sensitivity to DNA-damaging agents. Double mutants of ARP6, and members of the INO80 and SWR1 complexes, cause a significant reduction in repair efficiency, suggesting that ARP6 functions independently of SWR1-C and INO80-C. These findings support a novel role for ARP6 in DSB repair that is independent of the SWR1 chromatin remodeling complex, through an apparent RSC-C and MRE11-associated DNA repair pathway.

scholarly journals Acceleration or Brakes: Which Is Rational for Cell Cycle-Targeting Neuroblastoma Therapy?

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 750
Author(s):  
Kiyohiro Ando ◽  
Akira Nakagawara
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Progression ◽  
Parp Inhibitors ◽  
Cell Cycle Checkpoint ◽  
Mitotic Catastrophe ◽  
Malignant Neoplasms ◽  
Checkpoint Kinases ◽  
Molecular Features ◽  
Cycle Checkpoint

Unrestrained proliferation is a common feature of malignant neoplasms. Targeting the cell cycle is a therapeutic strategy to prevent unlimited cell division. Recently developed rationales for these selective inhibitors can be subdivided into two categories with antithetical functionality. One applies a “brake” to the cell cycle to halt cell proliferation, such as with inhibitors of cell cycle kinases. The other “accelerates” the cell cycle to initiate replication/mitotic catastrophe, such as with inhibitors of cell cycle checkpoint kinases. The fate of cell cycle progression or arrest is tightly regulated by the presence of tolerable or excessive DNA damage, respectively. This suggests that there is compatibility between inhibitors of DNA repair kinases, such as PARP inhibitors, and inhibitors of cell cycle checkpoint kinases. In the present review, we explore alterations to the cell cycle that are concomitant with altered DNA damage repair machinery in unfavorable neuroblastomas, with respect to their unique genomic and molecular features. We highlight the vulnerabilities of these alterations that are attributable to the features of each. Based on the assessment, we offer possible therapeutic approaches for personalized medicine, which are seemingly antithetical, but both are promising strategies for targeting the altered cell cycle in unfavorable neuroblastomas.

scholarly journals PEA15 Regulates the DNA Damage-Induced Cell Cycle Checkpoint and Oncogene-Directed Transformation

2014 ◽  
Vol 34 (12) ◽  
pp. 2264-2282 ◽  
Author(s):  
A. Nagarajan ◽  
S. K. Dogra ◽  
A. Y. Liu ◽  
M. R. Green ◽  
N. Wajapeyee
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Checkpoint ◽  
Cycle Checkpoint ◽  
Directed Transformation

scholarly journals ATM’s Role in the Repair of DNA Double-Strand Breaks

Genes ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1370
Author(s):  
Atsushi Shibata ◽  
Penny A. Jeggo
Keyword(s):  
Stress Responses ◽  
Ataxia Telangiectasia ◽  
Cell Cycle Checkpoint ◽  
Double Strand Breaks ◽  
Multiple Roles ◽  
Dna Double Strand Breaks ◽  
Ataxia Telangiectasia Mutated ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Cycle Checkpoint

Ataxia telangiectasia mutated (ATM) is a central kinase that activates an extensive network of responses to cellular stress via a signaling role. ATM is activated by DNA double strand breaks (DSBs) and by oxidative stress, subsequently phosphorylating a plethora of target proteins. In the last several decades, newly developed molecular biological techniques have uncovered multiple roles of ATM in response to DNA damage—e.g., DSB repair, cell cycle checkpoint arrest, apoptosis, and transcription arrest. Combinational dysfunction of these stress responses impairs the accuracy of repair, consequently leading to dramatic sensitivity to ionizing radiation (IR) in ataxia telangiectasia (A-T) cells. In this review, we summarize the roles of ATM that focus on DSB repair.

Mutation in the bimD gene of Aspergillus nidulans confers a conditional mitotic block and sensitivity to DNA damaging agents.

Genetics ◽  
1993 ◽  
Vol 134 (4) ◽  
pp. 1085-1096
Author(s):  
S H Denison ◽  
E Käfer ◽  
G S May
Keyword(s):  
Aspergillus Nidulans ◽  
Leucine Zipper ◽  
Temperature Sensitive ◽  
Sequence Motifs ◽  
Mitotic Progression ◽  
Dna Damaging Agents ◽  
Mitotic Block ◽  
Increased Sensitivity ◽  
Carboxyl Terminal ◽  
The Relationship

Abstract Mutation in the bimD gene of Aspergillus nidulans results in a mitotic block in anaphase characterized by a defective mitosis. Mutation in bimD also confers, at temperatures permissive for the mitotic arrest phenotype, an increased sensitivity to DNA damaging agents, including methyl methanesulfonate and ultraviolet light. In order to better understand the relationship between DNA damage and mitotic progression, we cloned the bimD gene from Aspergillus. A cosmid containing the bimD gene was identified among pools of cosmids by cotransformation with the nutritional selective pyrG gene of a strain carrying the recessive, temperature-sensitive lethal bimD6 mutation. The bimD gene encodes a predicted polypeptide of 166,000 daltons in mass and contains amino acid sequence motifs similar to those found in some DNA-binding transcription factors. These sequences include a basic domain followed by a leucine zipper, which together are called a bZIP motif, and a carboxyl-terminal domain enriched in acidic amino acids. Overexpression of the wild-type bimD protein resulted in an arrest of the nuclear division cycle that was reversible and determined to be in either the G1 or S phase of the cell cycle. Our data suggest that bimD may play an essential regulatory role relating to DNA metabolism which is required for a successful mitosis.

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