Labeling and Detection of Nucleic Acids

The highly sensitive non-radioactive DIG system allows specific detection Principle and of 0.01-0.03 pg DNA or RNA within 1-16 h with colorimetric BCIP/NBT applications detection (McGadey, 1970) or 15-30 min with chemiluminescent detection [Disodium 3- (4-methoxyspiro-{1,2 - dioxetane-3,2’-(5’-chloro) tricyclo [3.3.1.1 3’7]decan}-4-yl)phenyl phosphate (CSPD) or Disodium 2-chloro5-(4-methoxyspiro {1,2-dioxetane-3,2’-(5’-chloro)tricyclo [3.3.1.13’7] decan}-4-y1)-1-phenyl phosphate (CDP-Star) (Bronstein et al., 1989)] in dot-, slot-, Southern and Northern blots, avoiding any significant background on nylon membranes (Kessler et al., 1990; Holtke et al., 1990; Seibl et al., 1990; Muhlegger et al., 1990; Kessler, 1991; Holtke, 1995). Nitrocellulose membranes in combination with chemiluminescence substrates are less sensitive and require the addition of an enhancer [e.g., NitroBlock, from Tropix, Inc. (Holtke, 1995)].