Distribution of histone modifications within the imprinted Snurf–Snrpn 3-Mb region. (A) Scheme of the genomic region analyzed by ChIP followed by allele-specific qPCR. The coordinates on chromosome 7 are indicated (bottom), as well as the location of the different transcription units. Arrows indicate the direction of transcription for protein-coding genes. The star indicates the location of the IC and its associated differentially methylated region (DMR). The vertical gray bars on the axis indicate the positions of 35 loci analyzed by allele-specific qPCR. (B–F) Distribution of H3K4me2 (B), H3Ac (C), H4K20me3 (D), H3K9me3 (E), and H3K79me3 (F) on the paternally and maternally contributed Snurf–Snrpn genomic regions. ChIP experiments were performed using brain chromatin prepared from fetuses conceived by crossing JF1/Ms males × C57BL/6 females. Data are expressed as relative abundance and are normalized to input. Values are the mean of two independent ChIP experiments ± standard deviation. Gray areas identify the flanking genomic domains located outside of the Snurf–Snrpn imprinted interval. Black arrows indicate positions in the Snurf–Snrpn IC. The paternally and maternally contributed Snurf–Snrpn genomic regions are indicated by gray squares and black circles, respectively.
