Model Genetic Systems to Study DNA Repair

使用一种被称为RNA干扰的方法，我们特异性地耗尽了人类细胞的FANCJ DNA解旋酶，并表征了细胞对稳定g -四重体DNA结构的小分子化合物的敏感性。这项工作使我们能够阐明FANCJ解旋酶在维持染色体稳定性方面的新功能。由于携带FANCJ解旋酶基因纯合突变的个体患有一种以基因组不稳定和癌症为特征的遗传疾病——范可尼贫血，我们相信我们的研究结果为FANCJ的细胞途径提供了新的见解，这些途径有助于对抗体内出现的由DNA结构改变（如g -四联体）引起的复制应激。

Using an approach known as RNA interference, we have specifically depleted human cells of the FANCJ DNA helicase and characterized the sensitivity of the cells to a small molecule compound that stabilizes G-quadruplex DNA structures. This work enabled us to elucidate a novel functionof the FANCJ helicase in the manintenace of chromosomal stability. Since individuals carrying homozygous mutations in the FANCJ helicase gene have a genetic disorder known as Fanconi Anemia characterized by genomic instability and cancer, we believe our results shed new insights to the cellular pathways of FANCJ that serve to counter replciational stress due to alterante DNA structures such as G-quadruplexes that arise in vivo. We have also employed yeast as a model genetic system to study the role of the Werner syndrome helicase in DNA replciation and repair. This work has enabled us to characterize the catalytic requirements of WRN in a defined genetic DNA repair pathway that operates to provide cellular resistance to alkylating agents which impose replicational stress. Lastly, we have utilized mouse as a model genetic system to characterize the role of a helicase ortholog (RECQ1) found in humans whose biological significance is not well understood. Characterization of th eprimary mouse embryonic fibroblasts from RECQ1 knockout mice has revealed that the RECQ1 helicase has unique and important roles in genomic stability maintenance.