02 January 1998
Vol 279, Issue 5347

About The Cover

Gene expression can now be imaged in individual live mammalian cells with higher sensitivity than previously possible. Expression of a -lactamase reporter gene in Chinese hamster ovary cells is revealed by incubation with a membrane-permeant fluorogenic substrate. Cells expressing -lactamase fluoresce blue and nonexpressing cells fluoresce green. This technique can be used to clone cells by flow cytometry and to screen drug candidates. See 84. [Image: H.-C. Tran and G. Zlokarnik]