problem w/ oocyte expression

[Jun Li]

Hi, dear netters;
I am encountering a problem with oocyte expression system.
We have a membrane transport protein to be expressed in 
the xenopus oocyte. We had very good result before. Now, 
all of sudden, the oocytes stop its expression. There are
some difference between now and then. We have different
people doing mRNA preparation and injection. But we have 
tried everything to rule out the bad mRNA. The mRNA was
systhesized on either Ambion or strategene kit. The in vitro
lysate gave a good yield. So we start suspecting that
it has something to do w/ the oocyte.
we would appreciate if anyone out there can share some
their experience with us over this distressing problem.

Thanks in advance
Jun Li