How long will labelled oligos last?

[Dr. Michael T. MacDonell]

Bill:

I'll admit my first inclination was to lurk and see what other folks had to say
about this, but I realized that what would most likely come back would be
"theoretical" answers.  Theoretically, it should last a very long time.  In
practice, however, it is likely to be a different outcome.

People who have a lot of experience making oligos (I have personally made
probably in the neighborhood of 50,000), find that synthetic oligos seem to have
a half-life.  The most sensitive application seems to be PCR.  This is curious
since the restriction enzyme recognition should be the most sensitive, but it
doesn't appear to be.  Frequently we have found that an oligo that performs
beautifully as a PCR primer, will perform only acceptably after 8-9 months, and
may not prime at all after 18 months.  We have stored the oligos dried down at
room temperature, as -20C, in sterile water at -20C, and in 20% (v/v) MeCN at
-20C.  The outcome is approximately the same.

We have discussed this with quite a number of folks with the same level
of experience as we have, and the answer seems to have evaded us all. 
There are a couple of interesting published studies on synthetic
oligos, the best being Farrance et al (1989) Nucleic Acids Research,
but does not directly address the half-life issue.

Given all that, you might contact the folks at Cruachem, Ltd. in
Glasgow.  They might be able to provide you with more anecdotal
evidence derived from their experiences.  I will be VERY interested to
hear what others have to say.  Given my experience, I would say that
the oligo you mention will probably serve well as a probe for quite
some time, but as a primer for only less than a year.

Others?  It would be a very interesting subject to toss around for
awhile.  I would be very interested in hearing anecdotal information
from other users.

Best Regards!
Mike MacDonell, Ph.D.
Ransom Hill Bioscience, Inc.

In <58jfln$cqq at kwuz.nerc-keyworth.ac.uk> Bill Burnett <bbur at dml.ac.uk>
writes: 
>
>
>
>Orright ar kids....
>
>If I end label some oligo probes with fluorescein-dUTP and
>terminal transferase, how long will they last in the freezer?
>
>Any thoughts?
>
>B.
>
>
>
>-------------------------------------------------------
>Bill Burnett             bbur at dml.ac.uk
>Scottish Association for Marine Science
>P.O.Box 3, Oban, Argyll, Scotland
>
>

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