Nucleolus Blue™ DCS1 is a cell-impermeant fluorescent dye that selectively binds to RNA within the nucleolus, a non-membrane-bound nuclear compartment responsible for ribosomal RNA (rRNA) transcription and processing. Upon binding to RNA, the dye exhibits strong blue fluorescence, whereas its interaction with DNA results in only weak fluorescence, providing exceptional specificity for nucleolar RNA detection.

This dye is particularly useful for studying nucleolar morphology and function in dead or permeabilized cells. It enables clear visualization of nucleoli and can be used in conjunction with nuclear counterstains such as Nuclear Green™ LCS1 or Nuclear Red™ LCS1 to provide additional structural context. The nucleolus plays a critical role in cellular processes, including ribosome biogenesis, DNA damage response, autophagy, viral pathogenesis, and cellular senescence. Morphological changes in the nucleolus have also been implicated as potential biomarkers for cancer diagnostics. Nucleolus Blue™ DCS1 is compatible with fluorescence microscopy, flow cytometry, and high-content imaging assays, making it a valuable tool for researchers investigating nucleolar dynamics and cellular homeostasis in various biological and disease contexts.