I have successfully isolated and cultured primary prostate cells isolated from a transgenic mouse colony that contains my gene of interest under the control of the rat Probasin promoter. I am using the method described in http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3349876/pdf/main.pdf

Unfortunately, I have realized that I lose the expression of the gene cloned just after the Probasin promoter as soon as I put my cells in culture... I have already tried to treat the cells with various concentrations of DHT, but I haven't been successful in restoring the transgene expression. Does anybody have any suggestions? Thank you!