T/A cloning

[Martin Cann]

In article <4cr5d7$ue0 at news.doit.wisc.edu>, Helkor at facstaff.wisc.edu
(Helen Korsmo) wrote:

> We ligated an insert into a T-vector (after treating the insert for 30
minutes with Taq; in order to 
> put A's on the ends) and transformed DH5-alpha cells and plated out on
LB plate with IPTG and 
> X-gal.  We got several white colonies ( presumably these have insert in
the vector), but mostly 
> blue (vector alone).  Is it possible for T-vectors to ligate?

The wobbly T's on these vectors are notoriously unstable.  The cut vector
has a shelflife of 1-2 months and will not survive too many freeze-thaw
cycles.  Could this be it?

Martin