Help: Transfection into mammalian cells

[Jing Huang]

Hi, I am trying to co-transfect 2 plasmids into both 3T3 (fibroblasts) 
and C2 (myoblasts) cells.  I am doing transient transfection and I need
to be able to control both the ratio of the 2 plasmids and the absolute
copy number of each plasmid inside a single cell.  The ratio can be 
achieved by the calcium phosphate method which gets multiple copies of 
plasmids into a cell, while electroporation usually gets only 1 copy of 
plasmid into each cell.  Does anyone know how to limit the copies of 
DNA molecules in the Ca method?  and how to get more than 1 but defined 
number of plasmids by electroporation?  Thanks! and I will post a summary.

-Jing
jing at u.washington.edu