Sensitive and Rapid Detection of ß-Galactosidase Expression in Intact Cells by Microinjection of Fluorescent Substrate

Abstract

Bacterial ß-galactosidase, coded by lacZ, has become the reporter of choice for studies of transcriptional activity on the single cell level. Unfortunately, current detection methods, like X-gal cytochemistry cannot be applied to live cells since the hydrolysis product of X-gal is toxic and the method requires fixation and permeabilization of the cells. Furthermore, a long incubation time (hours to days) is required and the method has limited sensitivity¹. Other methods (immunocytochemical; introduction of fluorescent substrate by hypotonic shock) have also proven to be either incompatible with study of viable cells¹, or not tolerated by all cell types^2,3,4. We will report a method for detection of ß-galactosidase in living cells without affecting morphology, viability or proliferating capacity. A more detailed description of the method is found in reference 2.