title: Application of 7-amino-actinomycin D for the fluorescence microscopical analysis of DNA in cells and polytene chromosomes.
abstract: The cytochemical properties of a guanine-specific synthetic fluorescent analogue of actinomycin D, 7-amino-actinomycin D, have been studied in fixed and living preparations of L cells and polytene chromosomes of salivary glands of Chironomus thummi thummi and Drosophila lummei (Hackman). 7-Amino-actinomycin D has been shown to bind to DNA-containing structures, thereby inducing in them a bright red fluorescence. No specific fluorescence has been found in RNA-containing structures treated with this fluorescent probe. The fluorescence pattern of some regions of polytene chromosomes with a known nucleotide composition was analysed. It has been established that 7-amino-actinomycin D induces a very weak fluorescence in GC-poor chromosome regions of the Drosophila lummei toromere structure. Data indicating a nonlinear dependence between the fluorescence intensity of a stained chromosome region and the GC content in its DNA have been obtained. The influence of DNA nucleotide composition in a chromosome region on the fluorescence of 7-amino-actinomycin D is discussed. In combination with quinacrine staining and the Feulgen fluorescence reaction, treatment with 7-amino-actinomycin D provides useful information about the distribution of GC base pairs in the chromosome region under study.
mesh_terms: D000818:Animals; D002683:Chironomidae; D002843:Chromatin / Q000032:analysis; D002875:Chromosomes / Q000032:analysis*; D004247:DNA / Q000032:analysis*; D003609:Dactinomycin / Q000031:analogs & derivatives*; D004330:Drosophila; D066298:In Vitro Techniques; D007739:L Cells / Q000032:analysis; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods; D011796:Quinacrine; D012469:Salivary Glands / Q000032:analysis
chemical_list: D002843:Chromatin; D003609:Dactinomycin; C025942:7-aminoactinomycin D; D004247:DNA; D011796:Quinacrine