Transcriptional Repressor CTCF (CTCF) belongs to the CTCF Zinc-Finger Protein family. CTCF contains twelve C2H2-type zinc fingers and interacts with CHD8. CTCF is widely expressed in many tissues, and it is absent in primary spermatocytes. CTCF is involved in transcriptional regulation by binding to chromatin insulators and preventing interaction between promoter and nearby enhancers and silencers. CTCF plays an essential role in oocyte and preimplantation embryo development by activating or repressing transcription. In addition, CTCF is also indispensable in the epigenetic regulation and chromatin remodeling.