Intrachromosomal Probes for Mutagenesis by Alkylated DNA Bases Replicated in Mammalian Cells:  A Comparison of the Mutagenicities ofO4-Methylthymine andO6-Methylguanine in Cells with Different DNA Repair Backgrounds

1996 ◽  
Vol 9 (6) ◽  
pp. 980-987 ◽  
Author(s):  
Kara B. Altshuler ◽  
Colette S. Hodes ◽  
John M. Essigmann
2005 ◽  
Vol 77 (9) ◽  
pp. 2920-2927 ◽  
Author(s):  
Kateřina Cahová-Kuchaříková ◽  
Miroslav Fojta ◽  
Tomáš Mozga ◽  
Emil Paleček

2003 ◽  
Vol 23 (17) ◽  
pp. 6063-6074 ◽  
Author(s):  
Craig Spiro ◽  
Cynthia T. McMurray

ABSTRACT Previous studies have shown that expansion-prone repeats form structures that inhibit human flap endonuclease (FEN-1). We report here that faulty processing by FEN-1 initiates repeat instability in mammalian cells. Disease-length CAG tracts in Huntington's disease mice heterozygous for FEN-1 display a tendency toward expansions over contractions during intergenerational inheritance compared to those in homozygous wild-type mice. Further, with regard to human cells expressing a nuclease-defective FEN-1, we provide direct evidence that an unprocessed FEN-1 substrate is a precursor to instability. In cells with no endogenous defects in DNA repair, exogenous nuclease-defective FEN-1 causes repeat instability and aberrant DNA repair. Inefficient flap processing blocks the formation of Rad51/BRCA1 complexes but invokes repair by other pathways.


Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 530
Author(s):  
Marlo K. Thompson ◽  
Robert W. Sobol ◽  
Aishwarya Prakash

The earliest methods of genome editing, such as zinc-finger nucleases (ZFN) and transcription activator-like effector nucleases (TALENs), utilize customizable DNA-binding motifs to target the genome at specific loci. While these approaches provided sequence-specific gene-editing capacity, the laborious process of designing and synthesizing recombinant nucleases to recognize a specific target sequence, combined with limited target choices and poor editing efficiency, ultimately minimized the broad utility of these systems. The discovery of clustered regularly interspaced short palindromic repeat sequences (CRISPR) in Escherichia coli dates to 1987, yet it was another 20 years before CRISPR and the CRISPR-associated (Cas) proteins were identified as part of the microbial adaptive immune system, by targeting phage DNA, to fight bacteriophage reinfection. By 2013, CRISPR/Cas9 systems had been engineered to allow gene editing in mammalian cells. The ease of design, low cytotoxicity, and increased efficiency have made CRISPR/Cas9 and its related systems the designer nucleases of choice for many. In this review, we discuss the various CRISPR systems and their broad utility in genome manipulation. We will explore how CRISPR-controlled modifications have advanced our understanding of the mechanisms of genome stability, using the modulation of DNA repair genes as examples.


2015 ◽  
Vol 427 (3) ◽  
pp. 652-658 ◽  
Author(s):  
Charlène Lemaître ◽  
Evi Soutoglou
Keyword(s):  

1994 ◽  
Vol 14 (1) ◽  
pp. 68-76 ◽  
Author(s):  
K W Caldecott ◽  
C K McKeown ◽  
J D Tucker ◽  
S Ljungquist ◽  
L H Thompson

XRCC1, the human gene that fully corrects the Chinese hamster ovary DNA repair mutant EM9, encodes a protein involved in the rejoining of DNA single-strand breaks that arise following treatment with alkylating agents or ionizing radiation. In this study, a cDNA minigene encoding oligohistidine-tagged XRCC1 was constructed to facilitate affinity purification of the recombinant protein. This construct, designated pcD2EHX, fully corrected the EM9 phenotype of high sister chromatid exchange, indicating that the histidine tag was not detrimental to XRCC1 activity. Affinity chromatography of extract from EM9 cells transfected with pcD2EHX resulted in the copurification of histidine-tagged XRCC1 and DNA ligase III activity. Neither XRCC1 or DNA ligase III activity was purified during affinity chromatography of extract from EM9 cells transfected with pcD2EX, a cDNA minigene that encodes untagged XRCC1, or extract from wild-type AA8 or untransfected EM9 cells. The copurification of DNA ligase III activity with histidine-tagged XRCC1 suggests that the two proteins are present in the cell as a complex. Furthermore, DNA ligase III activity was present at lower levels in EM9 cells than in AA8 cells and was returned to normal levels in EM9 cells transfected with pcD2EHX or pcD2EX. These findings indicate that XRCC1 is required for normal levels of DNA ligase III activity, and they implicate a major role for this DNA ligase in DNA base excision repair in mammalian cells.


2009 ◽  
Vol 66 (6) ◽  
pp. 1010-1020 ◽  
Author(s):  
S. Tornaletti
Keyword(s):  

2001 ◽  
Vol 36 (9) ◽  
pp. 1483-1494 ◽  
Author(s):  
Rebecca L. Persinger ◽  
Robert Melamede ◽  
Ivan Bespalov ◽  
Susan Wallace ◽  
Douglas J. Taatjes ◽  
...  

Author(s):  
L. H. Thompson ◽  
K. W. Brookman ◽  
E. P. Salazar ◽  
J. C. Fuscoe ◽  
C. A. Weber

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