DNA Laddering - (Oct/28/2009 )

HI!

I need to extract genomic DNA from mammalian cells and run them on the gel. If there is DNA ladder after the cells were treated with drug, we can confirm that the drug cause the cells apoptosis.
Now I encountered a problem. The SDS in the lysis buffer I used in our lab to lyse the cells would precipitate after ethanol precipitation. After it precipitated it is very hard to get rid of it unless I add a lot of water or TE. In this case, the DNA concentration would be very low.
Does anyone have better protocol to do DNA laddering? And how much DNA is needed to load on the gel in order to see the ladder?

Thank you very much in advance for providing answers!

Olga

Why are you worried about the SDS?
My guess is that moderate amounts of SDS should not have any impact on that assay so removing it completely should not be necessary.