SJL mice

[Jeff Kramer]

Hello All. 

	I have a question for any mouse people that might be out there.  I've
been working with a transgenic mouse line, that were "prepared from pronuclei
of C57BL/6 x SJL F2 hybrid recipient fertilized mouse eggs."  That last bit was
straight from a paper from this laboratory.  We mated TG Fzeros with nTG
breeding stock C57BL/6 animals.  We had four TG males and 1 female.  The female
only brought 1 litter to the weaning stage, while the nTG females had "lots"
of successful litters.  The fellow before me had a lot of trouble getting the
F1's to have litters.  At least 2 out of 3 litters died, because the mothers
weren't lactating.  It got so bad, that the animals were getting too old to
breed, and we didn't have enough F2's to continue the line (for other reasons
as well).  that is when I started.  I brought in nTG C57BL/6 females, and
bred them with the old TG males, and got to the F3 generation, though they were
all hemizygous, due to the nontransgenic mothers.  So now I'm mating to get
to the F4 generation, and the mothers just aren't lactating.  I've had three
litters live to be weaned, and 14 litters died b/c mom wasn't lactating.  Now,
if our transgene is doing this, that could be interesting in a number of ways.
More likely, this could be just a strain-thing.  So after that long spiel,
here is my short question.  Does anyone with experience with SJL mice know of
a predisposition to NOT lactate?  Am I hoping for a nobel prize winning
observation when in actuality I've run across something any vivarium staff
member knows from experience?  thanks for the input...

								-Jeff

					Jeffrey A. Kramer, Ph.D.
					Wayne State University Medical Center
					C.S. Mott Center for Human Growth and
						Development
					275 E. Hancock
					Detroit, MI  48201
					jeff at compbio.med.wayne.edu
					http://compbio.med.wayne.edu/~jeff/