Mycoplasma MTases translocate to the human cell nuclei and methylate the human genome. (A) substrate specificity of Mhy1 (mCG), Mhy2 (mCG and AmCATGT), and Mhy3 (GATmC). Bisulfite DNA sequencing chromatograms of DNA substrates are shown. Stars indicate 5 mC. (B) confocal images of HT1080/Mhy1, HT1080/Mhy2, HT1080/Mhy3, HTR8/Mhy1, HTR8/Mhy3, and HTR8/mock cells. Upper left panel shows the condensed chromatin in a single HT1080/Mhy1 cell. Red, the V5 immunostaining. Blue, DAPI. (C) DNA Methylation-interference assay. HT1080/Mhy1, HT1080/Mhy2, HT1080/Mhy3 and HT1080/mock genomic DNA was digested using HpaII, MspI (a methylation-insensitive isoschizomer of HpaII), Sau3AI and MboI (a methylation-insensitive isoschizomer of Sau3AI). (D) methylation-specific PCR of a CPGI promoter region of the MMP2 gene in HT1080/Mhy1 and HT1080/mock cells. PCR products specific to methylated (M) and unmethylated (U) DNA are shown.