TY - JOUR T1 - Modulation of Genome Editing Outcomes by Cell Cycle Control of Cas9 Expression JF - bioRxiv DO - 10.1101/127068 SP - 127068 AU - Yuping Huang AU - Caitlin McCann AU - Andrey Samsonov AU - Dmitry Malkov AU - Gregory D Davis AU - Qingzhou Ji Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/04/12/127068.abstract N2 - Targeting specific chromosomal sequences for genome modification or regulation during particular phases of the cell cycle may prove useful in creating more precise, predictable genetic changes. Here, we present a system using a fusion protein comprised of a programmable DNA modification protein, Cas9, linked to a cell cycle regulated protein, geminin, as well as green fluorescent protein (GFP) for visualization. Despite the large size of Cas9 relative to geminin, cells were observed to express Cas9-GFP-geminin at levels which oscillate with the cell cycle. These fusion proteins are also shown to retain double-strand break (DSB) activity at specific chromosomal sequences to produce both indels and targeted integration of donor ssDNA. Most importantly, the ratio of ssDNA donor integration to non-homologous end joining (NHEJ) was observed to increase, suggesting that cell cycle control Cas9 expression may be an effective strategy to bias DNA repair outcomes. ER -