ERCC1-XPF Cooperates with CTCF and the Cohesin to Facilitate the Developmental Silencing of Imprinted Genes

Inborn defects in DNA repairare associated with complex developmental disorders whose causal mechanisms are poorly understood. Using an in vivo biotinylation tagging approach in mice, we show that the nucleotide excision repair (NER) structure-specific endonuclease ERCC1-XPF complex interacts with the insulator binding protein CTCF, the cohesin subunits SMC1A and SMC3 and with MBD2; the factors co-localize with ATRX at the promoters and control regions (ICRs) of imprinted genes during postnatal hepatic development. Loss of Ercc1or exposure to mitomycin C triggers the localization of CTCF to heterochromatin, the dissociation of the CTCF-cohesin complex and ATRXfrom promoters and ICRs,altered histone marks and the aberrant developmental expression of imprinted genes without altering DNA methylation. We propose that ERCC1-XPF cooperates with CTCF and the cohesinto facilitatet he developmental silencing of imprinted genes and that persistent DNA damage triggers chromatin changes that affect gene expression programs associated with NER disorders.