scholarly journals DNA damage in 3D constricted migration or after lamin-A depletion in 2D: shared mechanisms of repair factor mis-localization under nuclear stress

2016 ◽  
Author(s):  
Yuntao Xia ◽  
Jerome Irianto ◽  
Charlotte R. Pfeifer ◽  
Jiazheng Ji ◽  
Irena L. Ivanovska ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Nuclear Envelope ◽  
Nuclear Structure ◽  
Lamin A ◽  
Soft Matrix ◽  
Progeroid Syndromes ◽  
Standard Culture ◽  
Repair Factor ◽  
Insight Into

AbstractCells that migrate through small, rigid pores and that have normal levels of the nuclear structure protein lamin-A exhibit an increase in DNA damage, which is also observed with lamin-A depletion in diseases such as cancer and with many lamin-A mutations. Here we show nuclear envelope rupture is a shared feature that increases in standard culture after lamin-A knockdown, which causes nuclear loss of multiple DNA repair factors and increased DNA damage. Some repair factors are merely mis-localized to cytoplasm whereas others are partially depleted unless rescued by lamin-A expression. Compared to standard cultures on rigid glass coverslips, the growth of lamin-A low cells on soft matrix relaxes cytoskeletal stress on the nucleus, suppresses the mis-localization of DNA repair factors, and minimizes DNA damage nearly to wildtype levels. Conversely, constricted migration of the lamin-A low cells causes abnormally high levels of DNA damage, consistent with sustained loss of repair factors. The findings add insight into why monogenic progeroid syndromes that often associate with increased DNA damage and predominantly impact cells in stiff tissues result from mutations only in lamin-A or DNA repair factors.

scholarly journals Nuclear rupture at sites of high curvature compromises retention of DNA repair factors

2018 ◽  
Vol 217 (11) ◽  
pp. 3796-3808 ◽  
Author(s):  
Yuntao Xia ◽  
Irena L. Ivanovska ◽  
Kuangzheng Zhu ◽  
Lucas Smith ◽  
Jerome Irianto ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Dna Damage ◽  
Dna Repair ◽  
Opposite Effect ◽  
Cell Attachment ◽  
Collagen Fibers ◽  
Lamin A ◽  
Soft Matrix ◽  
Damage Marker ◽  
Nuclear Rupture

The nucleus is physically linked to the cytoskeleton, adhesions, and extracellular matrix—all of which sustain forces, but their relationships to DNA damage are obscure. We show that nuclear rupture with cytoplasmic mislocalization of multiple DNA repair factors correlates with high nuclear curvature imposed by an external probe or by cell attachment to either aligned collagen fibers or stiff matrix. Mislocalization is greatly enhanced by lamin A depletion, requires hours for nuclear reentry, and correlates with an increase in pan-nucleoplasmic foci of the DNA damage marker γH2AX. Excess DNA damage is rescued in ruptured nuclei by cooverexpression of multiple DNA repair factors as well as by soft matrix or inhibition of actomyosin tension. Increased contractility has the opposite effect, and stiff tumors with low lamin A indeed exhibit increased nuclear curvature, more frequent nuclear rupture, and excess DNA damage. Additional stresses likely play a role, but the data suggest high curvature promotes nuclear rupture, which compromises retention of DNA repair factors and favors sustained damage.

scholarly journals Division of Labor between SOS and PafBC in Mycobacterial DNA Repair and Mutagenesis

2021 ◽  
Author(s):  
Oyindamola O Adefisayo ◽  
Pierre Dupuy ◽  
James M Bean ◽  
Michael S Glickman
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Antibiotic Resistance ◽  
Division Of Labor ◽  
Transcriptional Regulatory Network ◽  
Lexa Repressor ◽  
Quinolone Antibiotics ◽  
Transcriptional Regulatory ◽  
Damage Response ◽  
Insight Into

DNA repair systems allow microbes to survive in diverse environments that compromise chromosomal integrity. Pathogens such as M. tuberculosis must contend with the genotoxic host environment, which generates the mutations that underlie antibiotic resistance. Mycobacteria encode the widely distributed SOS pathway, governed by the LexA repressor, but also encode PafBC, a positive regulator of the transcriptional DNA damage response (DDR). Although the transcriptional outputs of these systems have been characterized, their full functional division of labor in survival and mutagenesis is unknown. Here we specifically ablate the PafBC or SOS pathways, alone and in combination, and test their relative contributions to repair. We find that SOS and PafBC have both distinct and overlapping roles that depend on the type of DNA damage. Most notably, we find that quinolone antibiotics and replication fork perturbation are inducers of the PafBC pathway, and that chromosomal mutagenesis is codependent on PafBC and SOS, through shared regulation of the DnaE2/ImuA/B mutasome. These studies define the complex transcriptional regulatory network of the DDR in mycobacteria and provide new insight into the regulatory mechanisms controlling the genesis of antibiotic resistance in M. tuberculosis.

scholarly journals Erratum: Ubiquitous overexpression of the DNA repair factor dPrp19 reduces DNA damage and extends Drosophila life span

2017 ◽  
Vol 3 (1) ◽  
Author(s):  
Kathrin Garschall ◽  
Hanna Dellago ◽  
Martina Gáliková ◽  
Markus Schosserer ◽  
Thomas Flatt ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Life Span ◽  
Repair Factor

scholarly journals Lamin A/C Depletion Enhances DNA Damage-Induced Stalled Replication Fork Arrest

2013 ◽  
Vol 33 (6) ◽  
pp. 1210-1222 ◽  
Author(s):  
Mayank Singh ◽  
Clayton R. Hunt ◽  
Raj K. Pandita ◽  
Rakesh Kumar ◽  
Chin-Rang Yang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Replication Fork ◽  
Dna Damage Repair ◽  
Genomic Stability ◽  
Replication Stress ◽  
Lamin A ◽  
Replicative Stress ◽  
Damage Repair ◽  
Repair Factor ◽  
Recombination Pathway

The humanLMNAgene encodes the essential nuclear envelope proteins lamin A and C (lamin A/C). Mutations inLMNAresult in altered nuclear morphology, but how this impacts the mechanisms that maintain genomic stability is unclear. Here, we report that lamin A/C-deficient cells have a normal response to ionizing radiation but are sensitive to agents that cause interstrand cross-links (ICLs) or replication stress. In response to treatment with ICL agents (cisplatin, camptothecin, and mitomycin), lamin A/C-deficient cells displayed normal γ-H2AX focus formation but a higher frequency of cells with delayed γ-H2AX removal, decreased recruitment of the FANCD2 repair factor, and a higher frequency of chromosome aberrations. Similarly, following hydroxyurea-induced replication stress, lamin A/C-deficient cells had an increased frequency of cells with delayed disappearance of γ-H2AX foci and defective repair factor recruitment (Mre11, CtIP, Rad51, RPA, and FANCD2). Replicative stress also resulted in a higher frequency of chromosomal aberrations as well as defective replication restart. Taken together, the data can be interpreted to suggest that lamin A/C has a role in the restart of stalled replication forks, a prerequisite for initiation of DNA damage repair by the homologous recombination pathway, which is intact in lamin A/C-deficient cells. We propose that lamin A/C is required for maintaining genomic stability following replication fork stalling, induced by either ICL damage or replicative stress, in order to facilitate fork regression prior to DNA damage repair.

Lamin A/C Mutations Linked to Muscular Disease Result in Mechanically‐induced, Progressive Nuclear Envelope Rupture and DNA Damage in Muscle Fibers

2018 ◽  
Vol 32 (S1) ◽  
Author(s):  
Tyler Kirby ◽  
Ashley Earle ◽  
Greg Fedorchak ◽  
Philipp Isermann ◽  
Jan Lammerding
Keyword(s):  
Dna Damage ◽  
Nuclear Envelope ◽  
Muscle Fibers ◽  
Lamin A ◽  
Muscular Disease

scholarly journals Rescue of DNA Damage After Constricted Migration by DNA Repair Factor Overexpression

2019 ◽  
Vol 116 (3) ◽  
pp. 119a
Author(s):  
Yuntao Xia ◽  
Charlotte Pfeifer ◽  
Kuangzheng Zhu ◽  
Jerome Irianto ◽  
Dennis Discher
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Repair Factor

scholarly journals Ubiquitous overexpression of the DNA repair factor dPrp19 reduces DNA damage and extends Drosophila life span

2017 ◽  
Vol 3 (1) ◽  
Author(s):  
Kathrin Garschall ◽  
Hanna Dellago ◽  
Martina Gáliková ◽  
Markus Schosserer ◽  
Thomas Flatt ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Life Span ◽  
Repair Factor

scholarly journals Mlp-dependent anchorage and stabilization of a desumoylating enzyme is required to prevent clonal lethality

2004 ◽  
Vol 167 (4) ◽  
pp. 605-611 ◽  
Author(s):  
Xiaolan Zhao ◽  
Chia-Yung Wu ◽  
Günter Blobel
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Nuclear Envelope ◽  
Nuclear Pore ◽  
Asymmetric Distribution ◽  
Nuclear Pore Complexes ◽  
Damage Response ◽  
Pore Complexes

Myosin-like proteins 1 and 2 (Mlp1 and Mlp2) form filaments attached to the nucleoplasmic side of the nuclear pore complexes via interaction with the nucleoporin Nup60. Here, we show that Mlps and Nup60, but not several other nucleoporins, are required to localize and stabilize a desumoylating enzyme Ulp1. Moreover, like Mlps, Ulp1 exhibits a unique asymmetric distribution on the nuclear envelope. Consistent with a role in regulating Ulp1, removal of either or both MLPs affects the SUMO conjugate pattern. We also show that deleting MLPs or the localization domains of Ulp1 results in DNA damage sensitivity and clonal lethality, the latter of which is caused by increased levels of 2-micron circle DNA. Epistatic and dosage suppression analyses further demonstrate that Mlps function upstream of Ulp1 in 2-micron circle maintenance and the damage response. Together, our results reveal that Mlps play important roles in regulating Ulp1 and subsequently affect sumoylation stasis, growth, and DNA repair.

scholarly journals Western Faculty Profile: Dr. Murray Junop

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Violet Liu
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Molecular Mechanism ◽  
Associate Professor ◽  
Primary Research ◽  
X Ray ◽  
X Ray Crystallography ◽  
Dna Repair Proteins ◽  
Editorial Review ◽  
Insight Into

Dr. Murray Junop is an Associate Professor and the Associate Undergraduate Chair in the Biochemistry Department at Western University. His primary research focuses on using x-ray crystallography to determine macromolecular structures crucial for the repair of various types of DNA damage. Ultimately, understanding the structures of these DNA repair proteins not only sheds insight into their function and molecular mechanism, but also provides necessary information for developing new anticancer therapies. Dr. Junop teaches undergraduate and graduate level courses offered in the department of Biochemistry. Violet Liu, a Reviewer on the Editorial Review Board at WURJ-HNS, had the pleasure of interviewing Dr. Junop to learn more about his career in research and his advice to students.

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