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Transgenic Core Facility
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Direct
microinjection of DNA into the pronucleus of a mouse zygote is the
method most extensively used in the production of transgenic mice. If
the injected DNA integrates into the chromosomal DNA, at the one-cell
stage of the zygote, the transgenic mouse will express the injected DNA
in every cell including germ cells. The
preparation of the DNA, and the screening and care of the weaned mice
are the investigator’s responsibilities. The facility will
inject the DNA provided by the investigator into the pronuclei of fertilized mouse embryos. Our donor embryos are CD-1 mice purchased from
the Charles River Laboratory. DNA is injected into 80-100 fertilized
eggs. After an overnight incubation, normal two-cell embryos are
transferred into foster female mice and their pregnancies are
monitored. Two weeks after the birth of potentially transgenic pups, the
investigator will be notified of the number of pups. Upon weaning 3-4
weeks after birth, pups are separated and then released to the care of
the investigator. If
this procedure fails to produce at least one transgenic founder,
we will reinject DNA into 50-70 eggs at no additional cost to the
investigator. If no transgenic mouse is detected after the second trial,
a meeting will be held between the investigator, facility director, and
technical personnel to discuss further effects. Difficulties
in creating transgenic mice. a) The DNA preparation must be pure of any contaminant and sufficiently concentrated. b) The lethality of embryo death in utero in foster mice may be associated with the type of DNA construct used.
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