Repair of endonuclease- and transposon-induced DNA double strand breaks by host factors in Arabidopsis /
Abstract (Summary)The maize Ac/Ds transposable elements are members of the hAT transposon family. Ac/Ds transpose in diverse species and via a mechanism similar to that involved in V(D)J recombination. Here, we studied the repair of Ds transposition-induced hairpins by host factors in Arabidopsis. The results indicate that AtKu could position hairpin-opening to sites close to the hairpin apex, In the absence of AtMre11 or AtKu70, repair junctions have a higher frequency of small deletions (3-10bp) and larger deletions (11-50bp), respectively. Comparison of the repair of l-Scel- and Ds-induced DSB indicates that Ac transposase could influence Ds-induced DSB repair. In addition, analysis of I-Scel-induced DSB repair indicates that both AtKu70 and AtMre11 are critical for non-homologous end joining (NHEJ); AtKu70, but not AtMre11 affects its fidelity. In these respects, NHEJ in Arabidopsis resembles that in S. cerevisiae. However, in Arabidopsis, the repair junctions are error-prone, and microhomology-mediated end joining is not affected by AtKu70. Hence, its junction patterns are similar to those in mammals. These results indicate the dynamics of DSB repair among different organisms.
School:Iowa State University
School Location:USA - Iowa
Source Type:Master's Thesis
Date of Publication: