HELP! -- Protecting DNA on a transilluminator?
Earl J. Gubbins
earl.j.gubbins at abbott.com
Tue Jul 15 07:36:49 EST 1997
Vern Shellman wrote:
> I am having problems ligating my DNA fragments cut out of a gel. I
> get variable results that seem to relate to how long it takes to cut
> out the band. The fastest I can see and cut out a band is about 15
> seconds and by then I suspect there is already significant UV damage.
> Is there any way to protect my DNA during UV exposure?
A recent article in Biotechniques (Vol. 21 #5, pp. 898 - 903; 1996)
discussed the use of guanosine or cytidine to protect DNA from UV
damage. The authors claim that the addition of 1 mM of either to the
gel increases cloning efficiencies by 10-100X by protecting the DNA from
damage. I have started adding 1 mM cytidine (1:100 dilution of a 100 mM
stock solution) to my gels, and while I haven't done direct comparisons
it does seem to yield significantly more colonies after ligation &
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