Detection of the native <i>Alu</i> sequences after bisulfite conversion.

<p>(<b>A</b>). The PCR product was successfully amplified with the MSP primers specific to the methylated <i>Alu</i> sequences from bisulfite-treated DNA with different DNA quantities of 0.5 ng and 50 ng on DNA samples of breast (1) and colon (2) tumour tissues. (+): Recombinant plasmid containing the methylated <i>Alu</i> sequences used as template. (<b>B</b>). The PCR product was successfully amplified with the primers specific to the native <i>Alu</i> sequences from bisulfite-treated DNA of 50 ng input. However, no native <i>Alu</i> product was detected when the DNA input was 0.5 ng. PC: Positive control with DNA extracted from a blood sample as template. NTC: Negative control without DNA template. (<b>C</b>). Digestion of the PCR products from (B) with the <i>Hpa</i>II restriction enzyme, recognizing one CCGG site in the <i>Alu</i> sequences, indicated that some native <i>Alu</i> sequences remained after bisulfite conversion of a DNA input of 50 ng.</p> <p>(PDF)</p>