Germline null alleles of both Pygo1 and Pygo2 were generated by mating heterozygous floxed mice with the CMV-Cre mice [15]. The sequences of the primers used for genotyping PCR were: Pygo2 null allele, forward (F) CCTGGATTCTTGTTGCTGGTATG; reverse (R) AAGGTATTTGGTGCTCCGAGGG; Pygo2 WT or floxed allele, F TGTCTTGATGACAGCGTTTAGCC, R AGATTCAGTAAGCTGAGCCTGGTG; Pygo1 null allele, F AGTTTGAAATAGCGACGAGTTTGAG, R 5'-CACTTCTGCCCCTCTCTTTGC; Pygo1 WT or floxed allele, F AAGCGTGCCTCATCTCCATCCCTAAG, R GCCCTCCCCGACGTTTATATTG.