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Calcium phosphate transfection question - (May/24/2006 )

Hi - I'm new to BioForum, but I did a search and didn't see an old thread on this (I may have missed one, though) - so please excuse me if this has been done to death in the past!

When doing a calcium phosphate transfection, what do you take as the zero time point? I'm doing a time series and can't decide when "0" would be - when I add the plasmid/CaPO4 mixture or when I remove that and add fresh media?

Thanks!

-labmomnm-

I would take the time when u add the plasmid/CaPo4 mixture to the cells as the start of transfection, as zero point.

-scolix-

hi
basically the protocol should say sthg like replace by fresh medium 3 hours post transfection.
So 0 is the time point when you add the mixture.

-fred_33-

CaPO4 is a bit stressing for the cell, so depending on the experiment I would either consider time point 0 before doing transfection or as scolix and fred said after adding the plasmid, nevertheless, I wouldnt expect any significant expression or effect at that point other than the stress to the cell, correct me if am wrong

-tertu-

QUOTE (fred_33 @ May 25 2006, 03:36 AM)
hi
basically the protocol should say sthg like replace by fresh medium 3 hours post transfection.
So 0 is the time point when you add the mixture.



Thanks, everyone - I just wasn't sure how much plasmid the cells would take up right off the bat. I was mostly confused by the glycerol shock step, which is 4 hours after the plasmid/CaPO4 is added and would throw my time-course off a bit. But many protocols now skip the glycerol shock, so I'll stick with your ideas and take 0 as the initial plasmid hit. Thanks!

-labmomnm-