Re-derivation

Rederivation by Embryo Transfer

For a complete table listing schedules and number of mice needed for rederivation click here: (Rederivation By Days)

The transgenic core performs rederivations by embryo transfer. The embryos from animals, which are carrying or suspected of carrying pathogenic agents are removed and transferred into pathogen free animals. This method of embryo transfer is the only one, which will guarantee the removal of adventitious agents from your colony giving you pathogen free animals to work with. The transgenic core recommends this service for any line that has tested positive for pathogens, as well as any new lines being imported from other institutions to BU. Following is a schematic for rederivation via embryo transfer.

For a table listing rederivations during 2008-2012 (sample as example): click here

  • Schematic for re-derivation from live mice (e,g., infected with a pathogen):
    Day 1– Inject hormones to donor females(PMS).


    Day 3– Inject hormones to donor females(HCG) and set up with males. Set up pathogen-free females with vasectomized males.
    Day 4– Check females for vaginal plug to confirm mating. Isolate embryos from infected females, treat them to disinfect and transfer them into pathogen free females.
    Day 24– Pathogen free litters are born.
    Day 38– Eye bleeds, foster mothers to confirm removal of adventitious agents.
    Day 45– Wean pathogen free pups.
  • Schematic for re-derivation from frozen embryos:
    Day 1– Set up clean females with vasectomized males.
    Day 2– Check females for vaginal plug to confirm mating.
    Day 3– Thaw 8 cell embryos.
    Day 4– Transfer blastocyst stage embryos into clean females.
    Day 24– Pathogen free litters are born.
    Day 45– Wean pathogen free pups.
Recent Rederivations performed at our facility using frozen embryos:
P.I.
Date
# Thawed
# Born
# Tg
Re-derived
Comments
Strain
W. Colucci
1/05
100
5
1
Yes
Hetroz. embryos frozen
by an outside facility.
11bHSD2
V. Zannis
9/04
100
9
9
Yes
Frozen at BUSM
B+D,B+I
K. Ravid
7/05
96
10
10
Yes
Homoz. Frozen at BUSM
Aim1Tet#41

Boston University School of Medicine/Transgenic Knock Out Core Facility



Scientific Director of Transgenic/Knock out Core, Dr. Katya Ravid
Transgenic Specialist and Manager, Greg Martin

Primary teaching affiliate
of BU School of Medicine