Infected cells that are dying after puromycin selection - (May/21/2011 )

Hi All,
I infected jurkat cell lines with a lentiviral inducible plasmid containing my target gene to be overexpressed and a lentiviral inducible system codifying for a control GFP. After two days from the infection we started the puromycin selection.
After 7 days of puro treatment, most of the cells survived and they looked like in a really good shape. When we started to expand the cells they started to die...and after 7 days we had almost no cell. Can someone help me to find out a possible explanation to this phenomenon??

Thank you in advance for your help!
G

What gene are you overexpressing? Are the GFP control cells also dying?

Without knowing all the facts I would suggest that the reason your cells are dying is because the gene you are attempting to overexpress is causing a malfunction in the cell cycle. The result is that when the cells are not actively dividing the expression of your gene is not causing any problems, but when the cells are actively dividing you gene's product is causing cell cycle arrest and initiation of apoptotic pathways.