FIG. 5.

(A) Low-molecular-weight DNA isolated in the absence of RNase A in the purification protocol, treated with different enzymes, and electrophoresed on a 10% polyacrylamide gel. Lane M, a 20-bp ladder used as a molecular size standard; lane 1, control DNA purified in the presence of RNase A; lane 2, untreated DNA; lane 3, DNA treated with RNase H; lane 4, heat-treated DNA; lane 5, DNA treated with RNase A; lane 6, DNA treated with DNase I; lane 7, DNA treated with S1 nuclease. (B) Since the presence of low-molecular-weight DNA is hidden by the presence of RNA, hybridization was carried out to detect the low-molecular-weight DNA.