| Summary: | 碩士 === 東海大學 === 生物學系 === 92 === Abstract
Epidemiologic studies demonstrated that long-term exposure to arsenic induces many human diseases, including blackfoot disease, atherosclerosis, and cancers. Although evidences show an association between arsenic and cancer, the molecular mechanism is still unclear. It is widely accepted that cancer results from the accumulation of mutations in the genes. Sodium arsenite has been shown to induce oxidative DNA damages and DNA-protein crosslinks. In this study, we used the random amplified polymorphic DNA (RAPD) assay with ninety arbitrary primers to evaluate the effects on the genomic DNA of human lymphoblastoid cells exposed to sodium arsenite. The main changes in RAPD profiles following sodium arsenite treatments were a decrease and an increase in band intensity. Two RAPD primers (D11 and F1) were more discriminated the RAPD profiles between sodium arsenite-treated and control genomic DNA. The sequences of these loci amplified with primers D11 and F1 showed highly similar to human RB1CC1 and PACE4 genes. The DNA markers were purified for the molecular detection of sodium arsenite-induced DNA damage by nucleic acid hybridization. To confirm the effect of sodium arsenite on RB1CC1 and PACE4 genes, we examined the expression of these two genes by Northern blot and RT-PCR analysis. Sodium arsenite treatment could significantly up-regulate the expression of RB1CC1 in human lymphoblastoid cells. Taken together, our results demonstrated, for the first time, that RAPD is a good tool for the detection of genomic DNA alternations and direct screening of new molecular markers related to sodium arsenite-induced carcinogenesis
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