Cell permeable fluorescent dye with low cytotoxicity. Useful for staining DNA, chromosomes and nuclei. Can be used with chromomycin A3 (Prod. No. BML-GR302) to distinguish chromosomes by their total DNA concentration and their DNA base composition. Binds to A:T pairs in DNA. Also useful for controlling gene expression through binding to RNA aptamers inserted into 5' untranslated region of a messenger RNA. Increases the rate of channel-mediated Ca2+ efflux from junctional cytoplasmic reticulum vesicles. Ex(max): 346nm; Em(max): 460nm.