Linear vs. Circular DNA

Dr. Pamela Norton P_Norton at CALVIN.JCI.TJU.EDU
Fri Nov 25 16:19:45 EST 1994

>I would like to ask a question for which I am having a hard time finding 
>an answer to.  I was told that it was not possible to generate stable 
>mammalian cell lines with circular plasmid DNA, that it should be linearized 
>first.  Is there a reason for this?
>                        -Dave
>David J. Austin, Ph.D.      
>Department of Chemistry     austin at
>Harvard University
>Cambridge, MA 02138

        We have had reasonable success with stable transfection of circular
DNAs into more than one mammalian cell type, but I suppose this may be
cell-type specific. What cells do your sources who say that this can't be
done use? Apparently, homologous recombination in transfect
(electroporated) ES cells is greatly enhanced by prior linearization of the
plasmid. Is this what you are referring to?

        I would be greatly interested in hearing from anyone who has had
better success transfecting linear versus circular DNA.

Pamela A. Norton, Ph.D.             p_norton at            
Assistant Professor of Medicine             
Thomas Jefferson University
1020 Locust Street, JAH 365
Philadelphia, PA  19107

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