DNA methylation inheritance is the process of copying pre-existing methylation patterns onto newly replicated DNA strand after DNA replication. Dnmt1 is the DNA methyltransferase that methylate hemi-methylated CpG region, which occurs after DNA repairs and replication steps. The mouse Np95 also known as Uhrf1 is nuclear protein, which contains an ubiquitin-like domain, a methyl DNA binding domain, the SRA (SET- and RING-associated) domain, a cyclinA/E-cdk2 phosphorylation site, a Rb binding motif, and a ring finger domain. Np95 forms complexes with Dnmt1 and PCNA at replicating heterochromatic regions, and recruits Dnmt1 to hemimethylated DNA to maintenance of DNA methylation. Np95 interacts with Dnmt1, is essential for the maintenance and the epigenetic inheritance of DNA methylation.