The ability of the restriction endonuclease EcoRI to digest hemi-methylated versus fully cytosine-methylated DNA of the herpes tk promoter region

Regulation of gene transcription appears to be influenced by cytosine methylation in vertebrates. Gene systems that are particularly sensitive to DNA methylation could be helpful in elucidating the inactivation mechanism, and helpful in determining which CpG's or group of CpG's are involved in the actual inactivation of transcription. We have such a gene system, in which a transfected herpesvirus tk gene is functionally inactivated by a low amount of DNA methylation. (DBO)