stable transfectants - (Mar/27/2002 )

I selected stable transfectants, by using g418 800ug/ml for a period of 2months, they are looks fine,
suddenly they are started for dying, what is the reasons for this. my interst of gene, and neomycin is under the control of single promoter, ie CMV.
please any body suggest me some idea reagrading this.

First thing you can try is cutting down the G418 dosage to promote survival higher doses are used for the initial stages of selection for stable cell lines. Next you probably want to try to detect your gene of interest via western blot to chekc if you gene is still present.