Influence Of The Methylation Of GDNF Gene In Promoter Ⅰ Region On Its Transcription

Objective: To observe the methylation status of GDNF promoter I region in humanglioma, in order to explore the effect of changes of methylation on the transcription ofGDNF in glioma.Methods: Genesequencing detected the GDNF gene order in10cases of glioma and5normal brain tissues, to compare whether their genetic mutations have occurred; themethylation modified status of GDNF promoter I region in20cases of glioma (10cases oflow-level and10cases of high-level) and5cases of normal brain tissues were detectedthrough genesequencing after bisulfite modification. the methylation modified status ofGDNF promoter I region were detected before and after intervened by differentconcentrations of5-aza-CR in glioma U251cell lines, the GDNF mRNAexpression were detected by RT-PCR in each group.Results: The mutations of GDNF gene in promoter I region were not observed inglioma; the methylation of GDNF gene in promoter I region in normal brain tissues,low-level and high-level glioma are66.25±9.05%、86.25±8.73%、86.75±8.85%respectively. The methylation level in glioma was significantly higher when compared tonormal brain tissues(P﹤0.05);while there was no significant differences in high-andlow-level tissues. the methylation level of GDNF gene in promoter I region began todecline after applicating with5-aza-CR, the methylation level dropped significantly whenadding5μmol5-aza-CR, In contrary, the expression of GDNF mRNA researchedthe highest. the methylation level of GDNF gene in promoter I region were no longerchange when add a higher concentrations of5-aza-CR, but the expression of GDNF mRNAbegan to decline. Conclusion: Hypermethylation occuerred in GDNF promoter I region, and5-aza-CRcould change its methylation level,5-aza-CR play demethylation effect on GDNF. thechange of methylation level of GDNF gene in promoter I region might influence theexpression of GDNF in glioma cell.