ccctc binding factor ctcf is a ubiquitous zn finger containing protein with numerous recognized functions including but not limited to gene activation and repression enhancer blocking x chromosome inactivation and gene imprinting it is believed that the protein performs such a variety of functions by interacting with an array of very diverse proteins in addition ctcf undergoes several post translational modifications including poly adp ribosyl ation the parylated form of ctcf has recently been implicated in two important functions gene imprinting and control of ribosomal gene transcription here we summarize and critically discuss the available data on the interplay between ctcf and poly adp ribosyl ation in these two processes we consider the newly described phenomena in the broader context of parp s activities including the crucial role of protein parylation in the regulation of the genome methylation pattern.