Immunodetection of DNA with biotinylated RNA probes: a study of reactivity of a monoclonal antibody to DNA-RNA hybrids.
A quantitative, nonisotopic hybridization assay which measures specific DNA-RNA hybrids is described. A biotinylated RNA probe is reacted in solution with a DNA target and the labeled hybrids are immobilized onto a solid phase surface with an antibiotin antibody. Bound hybrids are detected with a beta-galactosidase-labeled monoclonal antibody against DNA-RNA hybrids and are quantitated with the addition of a fluorogenic substrate. In a model system using pSP65 or pGEM4 plasmids and transcripts, biotinylated RNA probes allowed detection of 5 pg of DNA in 10(6) pg of exogenous nucleic acids in 1000 min. Signals generated in the system depended on input target length. A nucleic acid target of 25 bases was still detectable in the assay. Human immunodeficiency virus type 1 (HIV-1) DNA was amplified in the polymerase chain reaction with Taq polymerase and a set of primers for the pol gene, one of which contained T7 RNA polymerase promoter sequences. A HIV-RNA probe of 326 bases was transcribed with T7 RNA polymerase using polymerase chain reaction (PCR) amplified DNA as a template. The RNA probe of 326 bases performed as well as a RNA probe of 2588 bases for detection of a DNA segment of 355 bp. For detection of dilutions of HIV-1 with PCR, a set of primers (outer set) was used for amplification of HIV-1 DNA. In a separate reaction a set of primers nested between the first set generated through PCR an amplified DNA fragment with the T7 promoter. This fragment was transcribed for the synthesis of a biotinylated RNA probe. This probe could then be reacted with material amplified with the outer set of primers. Ten copies of HIV-DNA could be detected with this procedure.
Coutlée
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Eudowood Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
Bobo
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L
Mayur
K
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Yolken
R H
RH
Viscidi
R P
RP
D000911:Antibodies, Monoclonal; D001710:Biotin / Q000378:metabolism; D004247:DNA / Q000032:analysis* / Q000276:immunology; D007124:Immunoenzyme Techniques; D007700:Kinetics; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D016133:Polymerase Chain Reaction; D015347:RNA Probes; D014158:Transcription, Genetic
D000911:Antibodies, Monoclonal; D015347:RNA Probes; D001710:Biotin; D004247:DNA