ZIM3 (zinc finger imprinted 3) is a KRAB-containing C2H2 zinc finger transcription factor involved in transcriptional regulation and early embryonic development. As a DNA-binding protein, ZIM3 contains Krüppel-associated box (KRAB) domains that function as a potent transcriptional repressor 1. The protein exhibits dependent recognition mechanisms where zinc fingers recognize DNA motifs in context-dependent manner, with variable spacing between sub-motifs affecting binding specificity 2. ZIM3 plays a critical role in human early embryogenesis, functioning as a regulator of major zygotic genome activation (ZGA). When overexpressed, ZIM3 activates totipotent features in human extended pluripotent stem cells, while simultaneous knockdown of ZIM3 and ZNF394 arrests human embryo development prior to the eight-cell stage 3. The gene exhibits tissue-specific and imprinted expression patterns, with maternal expression predominating in adult testes and localization within the imprinted PEG3/USP29 domain 45. Clinically, ZIM3's potent KRAB repressor domain has been leveraged as an exceptionally effective tool for CRISPRi-mediated gene silencing in research and therapeutic applications 167, enabling precise gene modulation in diverse cell types including cardiomyocytes for functional genomics studies.