FIG. 3.

The 5′ region of MAGE-A1 is protected against de novo methylation in cells capable of a high-level expression of the gene. The cosmid carrying MAGE-A1 was transfected unmethylated into MZ2-MEL2.2.5 cells. Bisulfite sequencing was used to test the methylation state of the MAGE-A1 transgene at two time points after transfection. The MAGE-A1 segments that were analyzed and the bisulfite sequencing results are represented as in Fig. 1. Histograms represent the overall percentages of methylated CpGs within each segment at the two points after transfection, deduced from the bisulfite sequencing results.