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) (PubMed:15070898, PubMed:18854139, PubMed:23059534, PubMed:30602440). Acts together with ZNF445, but ZFP57 plays the predominant role in imprinting maintenance. In contrast, in humans, ZNF445 seems to be the major factor early embryonic imprinting maintenance (PubMed:30602440). 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 (PubMed:15070898, PubMed:18854139, PubMed:23059534). Binds various differentially methylated regions (DMR), including the Snrpn DMR. Expressed in oocytes and in a subset of adult tissues. Expressed at high levels in testis, and at low levels in cerebellum. Present in sciatic nerve and spinal cord (at protein level). Expression peaks between 11 dpc and 17 dpc, and decreases from P0 to P28. Expressed in lung throughout embryonic development. At 12 dpc, expressed in spinal cord, dorsal root ganglia and sciatic nerve. At 15 dpc, highly expressed in all neural tissues. At P0, expressed in brain and spinal cord. Present in Schwann cells at 16 dpc and P0 (at protein level). Maternal product is present in preimplantation embryos. Expressed in pluripotent embryonic stem cells. Down-regulated when embryonic stem cells differentiate. Up-regulated by LIF. Down-regulated during differentiation of embryonic stem cells, or during retinoic acid-induced differentiation of F9 cells (at protein level). Regulated by JMJD1A, which mediates histone H3K9Me2 demethylation at its promoter, thereby activating expression. 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). Affects the maintenance of DNA methylation imprints. The absence of just the zygotic function causes partial neonatal lethality, whereas eliminating both the maternal and zygotic functions results in a highly penetrant embryonic lethality. In oocytes, its absence results in failure to establish maternal methylation imprints at the Snrpn imprinted region. Intriguingly, methylation imprints are reacquired specifically at the maternally derived Snrpn imprinted region when the zygotic Zfp57 is present in embryos (PubMed:18854139, PubMed:30602440). Double zygotic mutations of ZFP57 and ZNF445 are embryonically lethal and embryos show no gross morphological abnormalities but significant reduction in size and weight at 11.5 dpc, a phenotype more pronounced than in ZFP57 mutant mice with a more severe loss of impinting (PubMed:30602440). Belongs to the krueppel C2H2-type zinc-finger protein family. Numerous sequencing errors.