Influence of DNA methylation on transgene expression

DNA methylation plays an important role in gene expression in eukaryote. Bu t DNA methylation of transgene usually leads to target gene silencing in pl ant genetic engineering. In this research, reporter gene -glucuronidase (GU S) gene (uidA) was introduced into tobaccos via Agrobacterium-m beta ediate d transformation method, and the foreign uidA gene became inactive in some transgenic tobaccos. No mRNA of uidA was detected in these plants by Northe rn blotting analysis, and DNA methylation of promoter region was found. The results indicated that gene silencing might be caused by DNA methylation o f promoter.