Comparing cell # or DNA content - of pelleted cells (Dec/13/2009 )

Hi everyone,

I have performed boyden chamber migration assay and have collected cells that have migrated to the bottom of transwell (pelleted and frozen). Usually I would measure and compare the # of cells (of different transfected cell lines) migrated using the cyquant proliferation assay, in which the cyquant dye would permeate the cell and binds to the DNA and I then would take the reading in the spectrometer. However, I just came upon a problem.

The cells that I am working now is GFP-transfected cells and unfortunately, GFP and cyquant have very similar excitation and emission wavelengths, therefore, the GFP expressed by the cells would interfere with the cyquant reading.

Does anyone of you know another dye/method that I may use to compare the cell # or DNA content of the cells that I have already pelleted? I thought of BrdU but they only incorporate into DNA of actively proliferating cells, right?

It would be great if my cells don't go to waste. I just wish I have realized about the similar wavelenghts before I've done the experiment.

Thanks in advance.

Spate

Try propidium iodide (used for FACS).