In accord with a set of prespecified principles of cell synchrony induction, a three-step procedure was developed to arrest cells reversibly in the G2 phase of the cell cycle. Cultures of Chinese hamster ovary (CHO) cells were presynchronized in early S phase by sequential treatment with isoleucine deficiency and hydroxyurea blockades; then they were switched to medium supplemented with either ...

Primitive hematopoietic cells from several species are known to efflux both Hoechst 33342 and Rhodamine-123. We now show that murine hematopoietic stem cells (HSCs) defined by long-term multilineage repopulation assays efflux both dyes variably according to their developmental or activation status. In day 14.5 murine fetal liver, very few HSCs efflux Hoechst 33342 efficiently, and they are thus...

The fluorescent compound Hoechst 33342 is a substrate for many multidrug resistance (MDR) transporters and is widely used to characterize their transport activity. We have constructed mutants of the adenosine triphosphate (ATP) binding cassette (ABC)-type MDR transporter LmrA of Lactococcus lactis that are defective in ATP hydrolysis. These mutants and wild-type LmrA exhibited an atypical behav...

Mutation within the adult human stem cell (SC) compartment has been proposed as a factor in the initiation and promotion of carcinogenesis. Isolation of these cancer stem cells (CSCs) has proven difficult, limiting their subsequent phenotypic, functional, and genetic characterization. We have used the Hoechst 33342 dye efflux technique to isolate an epithelial side population (SP) from genitour...

Hoechst 33342 stain has been used previously in conjunction with fluorescence activated cell sorting to separate cell populations into the various phases of the cell cycle. The present experiments were designed to evaluate the toxicity of this stain in cells derived from solid KHT sarcomas which were untreated or irradiated prior to dissociation. In both untreated and irradiated cells, stain to...