Transcription regulator required to maintain maternal and paternal gene imprinting, a process by which gene expression is restricted in a parent of origin-specific manner by epigenetic modification of genomic DNA and chromatin, including DNA methylation. Acts by controlling DNA methylation during the earliest multicellular stages of development at multiple imprinting control regions (ICRs). Acts together with ZNF445. Required for the establishment of maternal methylation imprints at SNRPN locus. Acts as a transcriptional repressor in Schwann cells. Binds to a 5'-TGCCGC-3' consensus sequence and recognizes the methylated CpG within this element. Binds various differentially methylated regions (DMR), including the Snrpn DMR. Expressed in oligodendrocytes and at lower levels in astrocytes. The KRAB domain is required for function as transcriptional repressor. Zinc fingers 2 and 3 mediate recognition of the target element, ZF2 interacting with the 5' half (TGC) and ZF3 interacting with the 3' half (CGC). Belongs to the krueppel C2H2-type zinc-finger protein family.