Hoechst 33342 nucleic acid stain is a popular cell-permeant nuclear counterstain that emits blue fluorescence when bound to dsDNA. This dye is often used to distinguish condensed pycnotic nuclei in apoptotic cells and for cell-cycle studies in combination with BrdU. Hoechst 33342 and 33258 are quenched by BrdU. Fluorescence is enhanced upon binding to dsDNA at stretches of at least three AT base pairs, but no binding to stretches of two or more GC base pairs. The Hoechst dyes requires a [dA-dT]3-[dG-dC]1 sequence to enhance fluorescence, with binding to the bottom of the minor groove as a prerequisite. It is postulated that the bromine on BrdU (or the chlorine on CldU) deforms the minor groove, such that the dye molecule can no longer reach its optimal binding site. It has shown that the Hoechst dyes still bind (with an even higher affinity) to BrdU substituted DNA, but no fluorescence ensues. This has been used extensively to monitor cell cycle progression. The products may be used in fluorescence microscopy, microplate, cuvette, and flow cytometry applications. Nuclear yellow is more commonly used as a neuronal retrograde tracer
Solution:10 ml in water
10 ml ; 100mg
Solution and powder storage/stability
Solution:Stock solutions may be stored refrigerated or frozen, protected from light. Note: The Hoechst stains should not be resolubilized in phosphate-buffered saline (PBS), but dilute solutions of the dye may be used with PBS or other phosphate-containing buffers. Solutions of Hoeschst dye should be stored at 2–6°C, protected from light. Stock solutions in water are stable for at least 6 months when refrigerated. For long-term storage the stock solution can be aliquoted and stored at ≤–20°C.
Powder:Freeze (<-15 °C),Minimize light exposure
Celltechgen provides high-quality reagents and materials for research use only. Propidium iodide and Hoechst 33342 are known or suspected mutagens and should be used with appropriate precautions. For proper handling of potentially hazardous chemicals, please request the Safety Data Sheet (SDS) provided for the product.