Isolating The Differentially Methylated DNA Sequences Of Gastric Cancer And Bioinformatics Analysis

Objective To isolate the differentially methylated DNA sequences betweengastric cancer and adjacent normal gastric mucosa and analyze them with relative bioinformatics methods.Methods The differentially methylated DNA sequences between gastric cancer andadjacent normal gastric mucosa(>5cm) were isolated by methylation-sensitive-representational difference analysis(MS-RDA). The differentially methylated DNA sequences were cut and recovered with agarose gel recovery kit and then they were cloned into a pGEM-T vector. Subsequently, the differentially methylated DNA sequences was transformed into E.coli strain JM109 and Bacteria were taken up in LB medium and incubated. After Positive colonies were picked out and identified by PCR, the differentially methylated DNA sequences were sequenced. Similarities between the separated differentially methylated DNA sequences and the human genomic DNA were analyzed with Basic Local Alignment Search Tool (BLAST) and the relative Genes on Chromosome Map were located with NCBI Map Viewer.Results Three differentially methylated DNA sequences, CRS1308, CRS1309and CRS1310, were obtained. CRS1309 sequence and CRS1310 sequence were accepted by GenBank. The accession number of the sequence were AY887107 and AY887106. CRS1309 sequence was highly similar to the eleventh exon of LOC440683 (similarity rate, 98%), 3'end of LOC440887(similarity rate, 99%),and promoter and exon region of DRD5(94%). CRS1310 sequence was highly similar to with a CpG island(similarity rate, 98%), in ribosomal RNA, isolated from colorectal cancer by Minoru Toyota in 1999.Conelusions1. The methylation degree was different between gastric cancer and adjacent normal...