HELP! -- Protecting DNA on a transilluminator?

plxsrt at plxsrt at
Tue Jul 29 12:41:52 EST 1997

Betsy Alberty <alsbyte1 at> wrote:

>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?

An easy  way is to cut the fragment out by placing a plastic tray
between the transilluminator and the gel.  This reduces the intensity
of UV reaching the fragment (and hence reduces cross-linking).  I use
the gel tray from the electrophoresis tank but it depends upon what
kit you use as to whether you can do the same.  I still try to get the
fragment out of the gel as quickly as possible.  You can always  try a
test ligation and run this out on a gel to test your fragments ability
to ligate after excision. 

I've used this method with a number of different setups and it has
always given me ligatable DNA.

Hope this helps

Simon T

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