CTCFL,also named BORIS (for brother of the regulator of imprinted sites) is a paralogue of the 11 zinc-finger transcription factor,CTCF. It is predominantly expressed in spermatocytes in the testis,also can be found in tumors and cancer cell lines. It mainly participates in insulator function,nuclear architecture and transcriptional control,which probably acts by recruiting epigenetic chromatin modifiers. It has a key role in gene imprinting in male germline,by participating in the establishment of differential methylation at the IGF2/H19 imprinted control region (ICR). Directly binds the unmethylated H19 ICR and recruits the PRMT7 methyltransferase,leading to methylate histone H4 'Arg-3' to form H4R3sme2.