Zusammenfassung
Methylation of CpG dinucleotides within proximal promoters is often associated with transcriptional silencing. Methylation-dependent repression is well established for hypermethylated CpG island promoters that are characterized by a high density of CpG residues. The effect of CpG DNA methylation on CpG-poor promoters is less well characterized, probably due to the lack of convenient assay systems ...
Zusammenfassung
Methylation of CpG dinucleotides within proximal promoters is often associated with transcriptional silencing. Methylation-dependent repression is well established for hypermethylated CpG island promoters that are characterized by a high density of CpG residues. The effect of CpG DNA methylation on CpG-poor promoters is less well characterized, probably due to the lack of convenient assay systems to test promoter activities in vitro. In this report, we describe a novel luciferase reporter vector, pCpGL, which completely lacks CpG dinucleotides and can be used to study the effect of promoter DNA methylation in transfection assays. Whereas a traditional reporter vector that contains a large number of backbone CpG residues significantly represses a CpG-free promoter when methylated, our new reporter vector is only repressed due to the presence of functionally important, methylated CpG residues. The pCpGL vector provides a useful tool to study the effects of CpG methylation on CpG-rich and CpG-poor promoters.