摘要
The BRCA1 （Breast Cancer Anti-estrogen resistance-I）, early-onset gene is expressed in cells of breast and other tissue and helps to repair damaged DNA or destroy cells in cases DNA cannot be repaired. When the BRCA1 gene is damaged, then the DNA is not repaired appropriately and this enhances the risk for cancer. Fluorescence and UV-visible thermal studies were performed for WT （wild type） and MT （mutant type targets） full systems. The target DNAs used were in the form of short oligonucleotides, genomic DNA. The probe system was used for detection of WT and SNP alleles of human BRCAI [（170-190, G---~T） and （290-310, G---~T）]. The Cy5 dye attached to a probe oligonucleotide （10-mer） undergoes a fluorescence intensity change on hybridisation of the probe to the WT compared to MT targets. Our results indicate that the system consisting of the target sequence and the one probe oligonucleotides bearing the Cy5 dye assemble correctly at the specified target. Once the full system （probe and target） is arranged under suitable conditions, a red-shift emission and change in fluorescence intensity are seen at a suitable wavelength. Thermal studies also showed significant differences in T,, between WT and MT. The results suggest that the differences in the fluorescence intensity at 665 nm and the spectrophotometric T,,,cs） for the WT and MT can be attributed to the type of binding of the probe to the target. The systems were sensitive to single nucleotide polymorphisms and this may help in high throughput applications in genetic testing and molecular diagnostics.
