scholarly journals Enhanced Bacterial Immunity and Mammalian Genome Editing via RNA-Polymerase-Mediated Dislodging of Cas9 from Double-Strand DNA Breaks

2018 ◽  
Vol 71 (1) ◽  
pp. 42-55.e8 ◽  
Author(s):  
Ryan Clarke ◽  
Robert Heler ◽  
Matthew S. MacDougall ◽  
Nan Cher Yeo ◽  
Alejandro Chavez ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Genome Editing ◽  
Mammalian Genome ◽  
Dna Breaks ◽  
Double Strand Dna Breaks ◽  
Double Strand Dna

scholarly journals Enhanced bacterial immunity and mammalian genome editing via RNA polymerase-mediated dislodging of Cas9 from double strand DNA breaks

2018 ◽  
Author(s):  
Ryan Clarke ◽  
Robert Heler ◽  
Matthew S. MacDougall ◽  
Nan Cher Yeo ◽  
Alejandro Chavez ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Genome Editing ◽  
Dna Sequences ◽  
Mammalian Cells ◽  
Strand Break ◽  
Dna Breaks ◽  
Simple Method ◽  
Guide Rna ◽  
Highly Active ◽  
Double Strand Dna Breaks

SUMMARYThe ability to target the Cas9 nuclease to DNA sequences via Watson-Crick base pairing with a single guide RNA (sgRNA) has provided a dynamic tool for genome editing and an essential component of adaptive immune systems in bacteria. After generating a double strand break (DSB), Cas9 remains stably bound to it. Here we show persistent Cas9 binding blocks access to DSB by repair enzymes, reducing genome editing efficiency. Cas9 can be dislodged by translocating RNA polymerases, but only if the polymerase approaches one direction towards the Cas9-DSB complex. By exploiting these RNA polymerase-Cas9 interactions, Cas9 can be conditionally converted into a multi-turnover nuclease, mediating increased mutagenesis frequencies in mammalian cells and enhancing bacterial immunity to bacteriophages. These consequences of a stable Cas9-DSB complex provide insights into the evolution of PAM sequences and a simple method of improving selection of highly active sgRNA for genome editing.

scholarly journals Fine-Structure Mapping of Meiosis-Specific Double-Strand DNA Breaks at a Recombination Hotspot Associated With an Insertion of Telomeric Sequences Upstream of the HIS4 Locus in Yeast

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1115-1125 ◽  
Author(s):  
Fei Xu ◽  
Thomas D Petes
Keyword(s):  
Meiotic Recombination ◽  
Hydroxyl Groups ◽  
Sequence Specificity ◽  
Structure Mapping ◽  
Dna Breaks ◽  
Exonuclease Iii ◽  
Recombination Hotspot ◽  
Telomeric Sequences ◽  
Double Strand Dna Breaks ◽  
Double Strand Dna

Abstract Meiotic recombination in Saccharomyces cerevisiae is initiated by double-strand DNA breaks (DSBs). Using two approaches, we mapped the position of DSBs associated with a recombination hotspot created by insertion of telomeric sequences into the region upstream of HIS4. We found that the breaks have no obvious sequence specificity and localize to a region of ~50 bp adjacent to the telomeric insertion. By mapping the breaks and by studies of the exonuclease III sensitivity of the broken ends, we conclude that most of the broken DNA molecules have blunt ends with 3′-hydroxyl groups.

Expression of double strand DNA breaks repair genes in pterygium

2010 ◽  
Vol 32 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Anna Łękawa–Ilczuk ◽  
Halina Antosz ◽  
Beata Rymgayłło–Jankowska ◽  
Tomasz Żarnowski
Keyword(s):  
Dna Breaks ◽  
Double Strand Dna Breaks ◽  
Repair Genes ◽  
Double Strand Dna

Inside Back Cover: Double-Strand DNA Breaks Induced by Paracyclophane Gold(I) Complexes (Chem. Eur. J. 26/2017)

2017 ◽  
Vol 23 (26) ◽  
pp. 6459-6459
Author(s):  
Sebastian Bestgen ◽  
Carmen Seidl ◽  
Thomas Wiesner ◽  
Andreas Zimmer ◽  
Martina Falk ◽  
...  
Keyword(s):  
Dna Breaks ◽  
Back Cover ◽  
Double Strand Dna Breaks ◽  
Double Strand Dna

Roles of Caenorhabditis elegans WRN Helicase in DNA Damage Responses, and a Comparison with Its Mammalian Homolog: A Mini-Review

Gerontology ◽  
2015 ◽  
Vol 62 (3) ◽  
pp. 296-303 ◽  
Author(s):  
Jin-Sun Ryu ◽  
Hyeon-Sook Koo
Keyword(s):  
Dna Damage ◽  
Caenorhabditis Elegans ◽  
Werner Syndrome ◽  
Model Organisms ◽  
Current Status ◽  
Helicase Domain ◽  
Replication Forks ◽  
Dna Breaks ◽  
Double Strand Dna Breaks ◽  
Double Strand Dna

Werner syndrome protein (WRN) is unusual among RecQ family DNA helicases in having an additional exonuclease activity. WRN is involved in the repair of double-strand DNA breaks via the homologous recombination and nonhomologous end joining pathways, and also in the base excision repair pathway. In addition, the protein promotes the recovery of stalled replication forks. The helicase activity is thought to unwind DNA duplexes, thereby moving replication forks or Holliday junctions. The targets of the exonuclease could be the nascent DNA strands at a replication fork or the ends of double-strand DNA breaks. However, it is not clear which enzyme activities are essential for repairing different types of DNA damage. Model organisms such as mice, flies, and worms deficient in WRN homologs have been investigated to understand the physiological results of defects in WRN activity. Premature aging, the most remarkable characteristic of Werner syndrome, is also seen in the mutant mice and worms, and hypersensitivity to DNA damage has been observed in WRN mutants of all three model organisms, pointing to conservation of the functions of WRN. In the nematode Caenorhabditis elegans, the WRN homolog contains a helicase domain but no exonuclease domain, so that this animal is very useful for studying the in vivo functions of the helicase without interference from the activity of the exonuclease. Here, we review the current status of investigations of C. elegans WRN-1 and discuss its functional differences from the mammalian homologs.

scholarly journals Target-AID-Mediated Multiplex Base Editing in Porcine Fibroblasts

2021 ◽  
Author(s):  
Soo-Young Yum ◽  
Goo Jang ◽  
Okjae Koo
Keyword(s):  
Genome Editing ◽  
Cytidine Deaminase ◽  
Chromosomal Rearrangements ◽  
Dna Breaks ◽  
Base Editing ◽  
Multiple Loci ◽  
Double Strand Dna Breaks ◽  
Protospacer Adjacent Motif ◽  
Motif Site ◽  
Programmable Nucleases

Multiplex genome editing may induce genotoxicity and chromosomal rearrangements due to double-strand DNA breaks at multiple loci simultaneously induced by programmable nucleases, including CRISPR/Cas9. However, recently developed base-editing systems can directly substitute target sequences without double-strand breaks. Thus, the base-editing system is expected to be a safer method for multiplex genome-editing platforms for livestock. Target-AID is a base editing system composed of PmCDA1, a cytidine deaminase from sea lampreys, fused to Cas9 nickase. It can be used to substitute cytosine for thymine in 3-5 base editing windows, 18 bases upstream of the protospacer-adjacent motif site. In the current study, we demonstrated Target-AID-mediated base editing in porcine cells for the first time. We targeted multiple loci in the porcine genome using the Target-AID system and successfully induced target-specific base substitutions with up to 63.15% efficiency. This system can be used for the further production of various genome-engineered pigs.

scholarly journals DNA fragmentation of human spermatozoa: Simple assessment of single‐ and double‐strand DNA breaks and their respective dynamic behavioral response

Andrology ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 1287-1303
Author(s):  
Ana Tímermans ◽  
Rosana Vázquez ◽  
Fátima Otero ◽  
Jaime Gosálvez ◽  
Stephen Johnston ◽  
...  
Keyword(s):  
Dna Fragmentation ◽  
Behavioral Response ◽  
Human Spermatozoa ◽  
Dna Breaks ◽  
Double Strand Dna Breaks ◽  
Double Strand Dna

scholarly journals 59 Effect of Magnetic Field During Radiotherapy on Double-Strand DNA Breaks and Cell Proliferation on Prostate, Cervical, and Breast Cancer Cells

2019 ◽  
Vol 139 ◽  
pp. S27-S28
Author(s):  
Deepak Dinakaran ◽  
Sarah Baker ◽  
Andrei Ghila ◽  
Zhighang Jin ◽  
Michael Hendzel ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Magnetic Field ◽  
Cell Proliferation ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Dna Breaks ◽  
Double Strand Dna Breaks ◽  
Double Strand Dna
Sign in / Sign up

Export Citation Format

Share Document