Alternative-NHEJ Is a Mechanistically Distinct Pathway of Mammalian Chromosome Break Repair

By Nicole Bennardo, Anita Cheng, N. Huang, Jeremy M. Stark. PLoS Genetics, 2008

852 citations recorded by the source corpus.

Characterizing the functional overlap and mutagenic potential of different pathways of chromosomal double-strand break (DSB) repair is important to understand how mutations arise during cancer development and treatment. To this end, we have compared the role of individual factors in three different pathways of mammalian DSB repair: alternative-nonhomologous end joining (alt-NHEJ), single-strand annealing (SSA), and homology directed repair (HDR/GC). Considering early steps of repair, we found that the DSB end-processing factors KU and CtIP affect all three pathways similarly, in that repair is suppressed by KU and promoted by CtIP. In contrast, both KU and CtIP appear dispensable for the absolute level of total-NHEJ between two tandem I-SceI–induced DSBs. During later steps of repair, we find that while the annealing and processing factors RAD52 and ERCC1 are important to promote SSA, both HDR/GC and alt-NHEJ are significantly less dependent upon these factors. As well, while disruption of RAD51 causes a decrease in HDR/GC and an increase in SSA, inhibition of this factor did not affect alt-NHEJ. These results suggest that the regulation of DSB end-processing via KU/CtIP is a common step during alt-NHEJ, SSA, and HDR/GC. However, at later steps of repair, alt-NHEJ is a mechanistically distinct pathway of DSB repair, and thus may play a unique role in mutagenesis during cancer development and therapy.

Subfields: Molecular Biology

View Paper: https://www.semanticscholar.org/paper/ba7499dbe6b9a4ef97eb0172829ff5f145a62509

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In Molecular Biology

1. Sang Eun Lee
2. Rodney Rothstein
3. M. Jasin
4. J. Haber
5. S. Boulton
6. F. Batista
7. Chikashi Ishioka
8. Mitch McVey

Citations in the corpus

• Sources of DNA double-strand breaks and models of recombinational DNA repair. (2014, background): “The reader is encouraged to read several excellent reviews (Bennardo et al. 2008; McVey and Lee 2008; Mladenov and Iliakis 2011; Chiruvella et al. 2013; Decottignies 2013).”
• RIF1 Is Essential for 53BP1-Dependent Nonhomologous End Joining and Suppression of DNA Double-Strand Break Resection (2013, methodology): “To directly assess if RIF1 functions to promote 53BP1-dependent DSB repair by NHEJ, we employed an established DSB reporter assay in HEK293 cells that measures NHEJ-mediated repair between two tandem I-SceI sites (Bennardo et al., 2008).”
• Repair of strand breaks by homologous recombination. (2013, background): “…with MRN (Zhong et al. 1999) and CtIP (Yu et al. 1998) and importantly promotes both HR and SSA (Moynahan et al. 1999; Stark et al. 2004), as does CtIP (Sartori et al. 2007; Bennardo et al. 2008), suggesting that BRCA1 may also be involved in the initial step of end resection (Stark et al. 2004).”
• MMEJ repair of double-strand breaks (director’s cut): deleted sequences and alternative endings (2008, background): “Recent findings indicate that mammalian CtIP, which is important for DNA end processing, can promote MMEJ-like repair [ 36 ].”
• Analysis of BRCA1 Variants in Double-Strand Break Repair by Homologous Recombination and Single-Strand Annealing (2012, methodology): “Stark (City of Hope, Duarte, CA) [Bennardo et al., 2008; Stark et al., 2004] stably integrated into HeLa cells to make the HeLa–SSA cell line.”
• Repair Pathway Choices and Consequences at the Double-Strand Break (2015, neutral): “For example, Rad51 prevents Rad52-mediated annealing of complementary ssDNA in yeast [91,92], and RAD51 inhibition in mammalian cells upregulates RAD52-mediated SSA activity [17].”