How long does it take for the gene to lose? - (Jan/18/2007 )

Hi all,
I am doing some assays on some stable cell lines. The results were very strange after passaging for a few times. I checked the expression with RT-PCR and the gene was still there but the expression was very low (much lower than freshly collected from stable transfection)
I only used the cells for less than a month, and the gene seemed to be lost. Is anyone experiencing the same problem?
How can I maintain the gene in the cells for longer?
Thanks!

Hi,

...what you see is principally not unusual unfortunately; depending on the gene which is transfected, the cells may e.g. compensate the high expression or your original selection was not 100% clonal so that cells are selected with a lower expression in your culture.
What might be very time consuming but worth a try is to establish an inducible system like a tet-off system; so the gene of interest is just expressed when induced and the culture is more or less clonal. I'm currently thinking of this option myself but this might really be time-consuming.

Cheers and good luck!

Thank you!
I would try Tet-on-off system if I have more time~~