nicking DNA plasmids on purpose
mantei at neuro.biol.ethz.ch
Sat Mar 2 09:45:06 EST 1996
In article <31374522.58D1 at simmons.swmed.edu>, walberg at simmons.swmed.edu wrote:
> Sorry I missed the beginning of this, but if you want to isolate open
> circles (form II) then there are some published methods to do this.
> An interesting one was published in NAR in 1975 or 1976 or so
> by Phil Martens and David Clayton. They nicked circular DNA in the
> presence of ethidium using a strong visible light- a slide projector I
> think. I think they got it to work with very good efficiency with
> very little form III.
The procedure was more or less to have DNA plus fairly concentrated EtBr
(perhaps 10--50 ug/ml?) in a cuvette. Illuminate with a slide projector
about 10 cm away, meanwhile cooling with a fan or hairdrier. Times to get
nicked circles were in the range of minutes. The method was around at
least a year or two before 1975.
Dept. of Neurobiology, Swiss Federal Institute of Technology
CH-8093 Zurich, Switzerland
mantei at neuro.biol.ethz.ch Fax: +41-1-633-1046
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