The Human Retinoblastoma Gene Is Imprinted
Figure 1
Identification of a novel putative imprinted locus.
(A) Heatmap of the Infinium HumanMethylation27 BeadChip (Illumina) for the RB1 gene. The CpG sites representing CpG 85 show about 50% methylation in DNA from blood of the parents but are hypomethylated in DNA from blood of the patient. In all samples, CpG 42 is methylated and CpG 106 is unmethylated. Target ID of the CpG sites representing CpG 85: cg19427472, cg13431205, cg03085377, cg18481241; CpG 42: cg19447496, cg19296958; CpG 106: cg24937706, cg10552385, cg17055959. (B) Schematic representation of the 5′-region of the RB1 locus (not drawn to scale) and location of CpG islands (green boxes). Regular exons are shown in blue whereas the new exon 2B is shown in light blue. Open lollipops, unmethylated CpGs; filled lollipops, methylated CpGs; black arrows, transcription start sites. (C) Exon connection PCR. M, DNA length standard; +, with RT; −, without RT; arrowhead indicates the RT–PCR product that was used as template for sequencing; red arrows, location of RT–PCR primers.