Hoechst 33342

Description

Hoechst 33342 (bisbenzimide, HOE 33342) is a cell-permeant blue-emitting fluorescent dye that binds strongly to adenine-thymine-rich regions in the minor groove of double-stranded DNA. Although Hoechst 33342 can bind to all nucleic acids, AT-rich dsDNA strands enhance its fluorescence considerably.

Hoechst 33342 bound with DNA has excitation/emission maxima at 351/461 nm, respectively. The fluorescence intensity of Hoechst 33342 increases with the pH of the solvent. The unbound dye fluoresces in the 510–540 nm range. The green fluorescence of unbound dye may be observed when an excessive dye concentration is used or the sample is insufficiently washed out. The dye has a considerable Stokes shift between the excitation and emission spectrum, making it worthwhile in multicolor labeling experiments.

The additional ethyl group in Hoechst 33342 renders it more cell-permeant than DAPI and other Hoechst dyes. Hoechst 33342 exhibits a 10-fold greater cell permeability than Hoechst 33258. Hoechst 33342 is also less toxic than DAPI, which ensures a higher viability of stained cells.

Hoechst 33342 is used extensively in fluorescence microscopy and flow cytometry for staining chromosomes and nuclei in live and fixed cells. The dye is often used to distinguish condensed pycnotic nuclei in apoptotic cells and cell sorting.

Hoechst 33342 is quenched by bromodeoxyuridine (BrdU), commonly used to detect dividing cells. When BrdU is integrated into DNA, the bromine is supposed to deform the minor groove so that Hoechst dyes cannot reach their optimal binding site. This property of Hoechst 33342 is used to study cell-cycle progression.

The commonly used dye concentration to stain bacteria or eukaryote cells is 0.1–10 μg/mL.

We offer Hoechst 33342 as a powder (1H010), a concentrated 10 mg/mL (2G010), and a ready-to-use (1B410) aqueous solutions.

Chemical Properties

yellow powder

Uses

Hoechst 33342 is an A:T-specific DNA minor groove ligand that is a widely used fluorochrome for visualizing cellular DNA. Excitation of the dye occurs around 350 nm with an emission maxima around 461 nm. Hoechst-33342, unlike other Hoechst dyes, is more lipophillic due to an additional ethyl group. The compound has been observed to displace several known DNA intercalators. Adriamycin has been shown to disrupt the DNA dye update. The compound can be used in sorting living cells based on DNA content by FACS, in the visualization of chromatin distribution in living cells, to detect BrdU incorporation into cells, the visualization of fixed cells by microscopy, and to study the initial stages of apoptosis and cell-cycle distribution. In addition to Hoechst-33342''s fluorescent capability, the

Uses

Hoechst 33342 is useful for staining DNA, chromosomes and nuclei. May be used for fluorescence microscopy or flow cytometry. Suitable for vital DNA staining of a variety of cell types and as a probe of membrane permeability in mammalian cells.

Definition

ChEBI: 2'-(4-ethoxyphenyl)-5-(4-methylpiperazin-1-yl)-2,5'-bibenzimidazole is a bibenzimidazole and a N-methylpiperazine. It has a role as a fluorochrome. It is functionally related to a pibenzimol.

Biological Activity

Cell permeable: yes', 'Primary Target
Adenine-thymine-specific fluorescent stain', 'Product does not compete with ATP.', 'Reversible: no

Safety Profile

Mutation data reported. Whenheated to decomposition it emits toxic vapors of NOx.

Abs/Em Maxima

351 (complex)/461 (complex) nm