Zinc Finger Nuclease induced DNA double stranded breaks and rearrangements in MLL

Autor: Bay Ho, Shyh Jen Shih, To Uyen Do, Andrew T M Vaughan
Rok vydání: 2012
Předmět:
Zdroj: Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis. 740:34-42
ISSN: 0027-5107
DOI: 10.1016/j.mrfmmm.2012.12.006
Popis: Radiation treatment or chemotherapy has been linked with a higher risk of secondary cancers such as therapy related Acute Myeloid Leukemia (tAML). Several of these cancers have been shown to be correlated to the introduction of double stranded breaks (DSB) and rearrangements within the Mixed Lineage Leukemia (MLL) gene. We used Zinc Finger Nucleases (ZFNs) to introduce precise cuts within MLL to examine how a single DNA DSB might lead to chromosomal rearrangements. A ZFN targeting exon 13 within the Breakpoint Cluster Region of MLL was transiently expressed in a human lymphoblast cell line originating from a CML patient. Although FISH analysis showed ZFN DSB at this region increased the rate of MLL fragmentation, we were unable to detect leukemogenic rearrangements or translocations via inverse PCR. Interestingly, gene fragmentation as well as small interstitial deletions, insertions and base substitutions increased with the inhibition of DNA-PK, suggesting repair of this particular DSB is linked to non-homologous end joining (NHEJ). Although mis-repair of DSBs may be necessary for the initiation of leukemogenic translocations, a MLL targeted DNA break alone is insufficient.
Databáze: OpenAIRE