Kan resistant plasmid growing in Amp

Jayakumar, R R.Jayakumar at RoswellPark.org
Thu Mar 3 00:34:11 EST 2005

How extraordinary?  I am not talking about the pEGFP-C1 plasmid growing on ampicillin plates.  But the fact that I mistakenlyy plated a E.coli strain carrying pEGFP-N1 on a plate with ampicillin and contrary to your observation othing grew on it.  It is based onthe same backbone as yours and didn ot show any growth on ampicillin. I am not aware of the differences between pEGFP-N1 aand pEGPF-C1, but the difference could explain why your's is growing on ampicillin and mine is not.

	-----Original Message----- 
	From: owner-methods at hgmp.mrc.ac.uk on behalf of Kyle Legate 
	Sent: Wed 3/2/2005 5:39 PM 
	To: methods at hgmp.mrc.ac.uk 
	Subject: Kan resistant plasmid growing in Amp

	Has anyone experienced this before? I can't find an explanation, and I
	would really like one. I am cloning in pEGFP-C1, which contains a Kan
	resistance cassette. I cut, ligated, plated, mini-prepped and
	maxiprepped, all using Amp by default because 90% of my plasmids encode
	Amp resistance. However, when I was making the data sheet for the new
	plasmid I discovered that it encodes Kan resistance, not Amp resistance.
	How could this be? How could a Kan resistant plasmid be amplified in
	Amp-containing media?
	I am sure I didn't accidentally use a Kan stock, and I am sure I have
	the correct product. I am not the only person who has experienced this;
	a colleague did the exact same thing (different Kan resistant plasmid)
	late last year.

More information about the Methods mailing list