TROPLIST: Morpholino losing activity in solution over time

[ilblitz@uci.edu]

Hi Jon,

Question(s):  Can the vials that MOs were shipped in, which I think are
some sort of plastic, tolerate the autoclaving you suggest?  And second,
what about the fluorescein modification carried on this particular MO?

Ira

> Hi folks, it's Jon from Gene Tools.
>
> We've learned that Morpholinos can associate with the inside walls of
> their containers, decreasing the solution concentration.  Many oligos
> don't do this, but it has occurred often enough that we now suggest
> keeping your Morpholino solutions at room temperature.  People whose
> labs have switched from cold storage to room temperature storage haven't
> been reporting any more problems with loss of activity.  If you have an
> oligo that has lost activity and the heating protocol Ira wrote about
> isn't bringing the activity back, try autoclaving the solution (with the
> vacuum dry cycle disabled).  Morpholinos can take the heat, though I
> wouldn't do it routinely, and the solvent collisions might be energetic
> enough to knock the oligos off the walls.
>
> For storage, I would wrap the vial closure in Parafilm (to help keep
> microbes out) and put the oligos in a dark box (to avoid photobleaching
> fluorochromes) on a lab shelf.  They should be fine for years that way.
>
> Best wishes,
>
>   - Jon
> jmoulton@gene-tools.com
>
> Dear Troplisters,
>
> I would like to ask you if you have found that some of your morpholino
> oligos might have lost their "activity" over time?  I have just determined
> that a morpholino I have been keeping at -20oC for the past 5 years and
> now have a reason to dig out for an experiment, no longer has the youthful
> vigor it once did.  I am aware that many people heat their morpholinos to
> 65oC for a short time before injecting, to improve solubility, etc.  This
> also failed to divert my embryos from their normal development.  So I
> thought I'd send out this email to see what others in the community have
> experienced.  Thanks for any comments you might have.
>
> Sincerely,
>
> Ira
>
>
>