A highly sensitive, nonradioactive DNA labeling and detection system.

A highly sensitive method for detecting specific nucleotide sequences was recently developed. The method uses digoxigenin-labeled nucleic acid probes for hybridization to immobilized target nucleic acids. Probes can be labeled by the random-primed method, nick translation, oligonucleotide tailing, cDNA synthesis, photodigoxigenin or SP6/T7/T3 polymerase-mediated transcription. Hybrids are detected by an enzyme-linked immunoassay using an anti-digoxigenin antibody conjugate. Visualization of the bound antibody is accomplished by an enzymatic color reaction, enzymatic chemiluminescent reaction or immunofluorescence, depending on the antibody conjugate and enzymatic substrate used. Here we report the successful application of this technology in the detection of specific cloned DNA in colony and plaque hybridizations, specific detection of a single mRNA species in Northern blots and single-copy gene detection in genomic Southern blots.