MS3: Double strand break repair is sustained when known DNA repair pathways are blocked
POSTER PRESENTATION (Video):
PRESENTER: Ron Babu
AUTHORS: Ronald Benjamin, Sara G. Trimidal, Atoshi Banerjee, Ji Eun Bae, Elizabeth Kong, Aaron Singer, Tyler S. Williams, Xiaogang Wu, Corey Geurink, Shang Shen, Edwin C. Oh, Hong W. Deng and Martin R. Schiller
MENTOR: Martin R. Schiller
Genome editing with engineered nucleases (GEEN) is a promising new biotechnology. We use Transcription activator-like effector nucleases (TALEN) to introduce double strand breaks (DSB)s at targeted genomic sites. Nonhomologous end-joining (NHEJ) pathways repair the breaks introducing indels into the genome. When the known NHEJ pathways (C-NHEJ and A-NHEJ ) are blocked, edits are still observed suggesting that there is redundancy between the two pathways or that a third pathway exists. To test among these possibilities, we engineered a NHEJ reporter system. C-NHEJ was blocked in XRCC4 knockout cells and A-NHEJ was blocked pharmacologically with mirin. Assessment of the genomic edits by reporter fluorescence and next generation sequencing revealed that approximately 50% of the NHEJ edits remained upon inhibition of both NHEJ pathways. RNAseq analysis identified differentially expressed genes. However, when both NHEJ pathways were blocked, genes from several pathways including chromatin assembly, p53 signalling, and metabolic pathways were differentially expressed and are likely part of the mechanisms to maintain robust NHEJ.