DAPI (CAS 28718-90-3)

DAPI, or 4′,6-diamidino-2-phenylindole, is a fluorescent stain that binds strongly to the adenine-thymine rich regions in DNA, making it a valuable tool in cell biology and molecular genetics research. Its ability to emit a bright blue fluorescence upon binding to double-stranded DNA is exploited extensively in fluorescence microscopy and flow cytometry, providing a means to visualize and quantify nuclear and chromosomal material within cells. The mechanism by which DAPI operates involves intercalating between the bases of DNA, with a particular affinity for A-T clusters, where it aligns parallel to the DNA strands. This specific binding enhances its fluorescence emission at a peak wavelength of about 461 nm when excited by ultraviolet light. Researchers utilize DAPI to study cell cycle progression, apoptosis, and other cellular processes that involve changes in nuclear architecture. Its application extends to various techniques such as chromosome counting, nuclear localization studies, and the detection of DNA in cellular homogenates. DAPI′s ability to rapidly penetrate live or fixed cells without the need for harsh treatment makes it an indispensable tool in the arsenal of techniques for studying cellular morphology and genetic material under a variety of experimental conditions. This makes DAPI an essential stain in the field of cytogenetics and other research disciplines where detailed nuclear visualization is necessary.

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