A single-strand conformation polymorphism method by capillary electrophoresis with laser-induced fluorescence for detection of the T1151A mutation in hMLH1 gene Mutation of hMLH1 gene plays an important role in human tumorigenesis. A highly sensitive single-strand conformation polymorphism (SSCP) method for detection of the T1151A mutation in exon 12 of the hMLH1 gene was for the first time developed employing laser-induced fluorescence capillary electrophoresis (LIF-CE). Effects of the concentration of linear polyacrylamide solution, running temperature, running voltage and the addition of glycerol on SSCP analysis were investigated, and the optimum separation conditions were defined. Thirty colorectal cancer patients and eight lung cancer patients were screened and the T1151A mutation was found in four of them. Based on CE-sequencing the mutation was further confirmed. To our knowledge, this is for the first time that the T1151A mutation is found in lung cancer. Our method is simple, rapid, and highly sensitive and is well suited to the analysis of large numbers of clinical samples.
IntroductionThe human hMLH1 gene plays a key role in the human DNA mismatch repair system, which recognizes and replaces mispaired nucleotides in DNA [1]. The inactivation of the gene results in increased genetic instability, which in turns leads to an increased rate of mutation in "gatekeeper" genes that regulate cell proliferation and death, and gives rise to cancer [2]. Searching for mutations of the hMLH1 gene has become more and more important in deciphering the genetic background of various cancers. Kuyper et al. [9]. The advantages of capillary electrophoresis instead of PAGE are speed, automation, resolution, and reproducibility. LIF detection has a 100-1000 times higher sensitivity than UV detection, and is widely applied in SSCP-CE [10][11][12][13][14][15]. Recently, published reports focused mostly on the effects of temperature, voltage, pH and DNA chain length on SSCP-CE performance [16,17]. To our knowledge, there are no reports on the systematic investigation of the effects of glycerol on SSCP-CE analysis though it is well-known that the addition of glycerol to sieving medium can enhance the resolution of single-strand DNA [10,11,14,15] and double-strand DNA [18,19].SSCP in combination with LIF-CE has been successfully applied to the analysis of many human genes, such as p53 gene [10,11]