The family of Heterochromatin protein 1 (HP1) proteins is a family of highly conserved heterochromatin-associated non-histone chromosomal proteins ,which has important functions in nucleus. These functions include gene activation or repression,regulation of binding of cohesion complexes to centromere,sequestration of genes to nuclear periphery,and heterochromatin formation and propagation. Much evidence shows that HP1 proteins interact with numerous proteins including methylated histones,histone methyltransferases and so on. CBX3 is one of the paralogues of HP1 proteins