Optical Studies of the interaction of 4'-6'-diamidino-2-phenylindole with DNA and metaphase chromosomes

The optical absorption and fluorescence characteristics of 4'-6-diamidino-2-phenylindole (DAPI) with DNA and chromosomes were studied. There is a decrease in extinction coefficient and chift in the absorption spectra to a higher wavelength when the dye binds to DNA. The fluorescence of DAPI is...

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Bibliographic Details
Published inChromosoma Vol. 60; no. 1; p. 15
Main Authors Lin, M S, Comings, D E, Alfi, O S
Format Journal Article
LanguageEnglish
Published Austria 07.03.1977
Subjects
Adenine Nucleotides - analysis
Amidines
Animals
Binding Sites
Bromodeoxyuridine
Chromosomes - analysis
DNA - analysis
Fluorescent Dyes
Humans
Hydrogen-Ion Concentration
Indoles
Mice
Mitosis
Polynucleotides - analysis
Spectrometry, Fluorescence
Staining and Labeling
Thymine Nucleotides - analysis
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Summary:The optical absorption and fluorescence characteristics of 4'-6-diamidino-2-phenylindole (DAPI) with DNA and chromosomes were studied. There is a decrease in extinction coefficient and chift in the absorption spectra to a higher wavelength when the dye binds to DNA. The fluorescence of DAPI is enhanced by both A-T and G-C base-pairs. The enhancement by A-T rich is significantly greater than by G-C rich DNA. The chromosomes and the constrictions of human chromosomes 1 and 16; these regions are known to contain A-T rich DNA and show dull fluorescence when treated with quinacrine. This dye may be useful for identifying A-T rich region in chromosomes. The fluorescence of DAPI bound to polynucleotides or chromosomes is partially quenched by the introduction of BrdU. This suppression of dye fluorescence allows optical detection of sister chromatid exchanges and chromosome region containing DNA with an unequal distribution of thymidine between polynucleotide chains after BrdU incorporation.
ISSN:0009-5915
DOI:10.1007/BF00330407