B6;129S-Rap1a^tm1Morz Rap1b^tm1Morz/J

Stock number: 021066
Research areas: Neurobiology Research

Description

These Rap1 double floxed mice possess loxP sites flanking exons in the RAP-related protein (Rap)-1a (Rap1a) and -1b (Rap1b) genes. This strain may be useful for studying synaptic plasticity and changes in cortical inputs to the lateral amygdala.

Detailed description

These Rap1 double floxed mice possess loxP sites flanking exons 2-3 of the RAP-related protein-1a (Rap1a) gene and loxP sites flanking exon 1 of the RAP-related protein-1b (Rap1b) gene. RAP1 is a small GTPase that has been found in both presynaptic and postsynaptic terminals. It has been implicated in regulation of AMPA receptor (AMPAR) trafficking, long-term potentiation (LTP) of synaptic transmission in the hippocampus, and spatial learning. Mice that are homozygous for these alleles are viable and fertile. When these mutant mice are bred to mice that express Cre recombinase, resulting offspring will have Rap1a exons 2-3 and Rap1b exon 1 deleted in cre-expressing tissues.

For example, when crossed to a strain expressing Cre recombinase in the forebrain, double Rap1 KO mice exhibit impaired fear learning due to alterations in cortical input to the lateral amygdala.

Development

A targeting vector was designed to insert a single loxP site upstream of exon 2, and a loxP-flanked neomycin resistance (neo) cassette downstream of exon 3 of the RAP-related protein-1a (Rap1a) gene. The construct was electroporated into 129S/SvEv-derived MM13 embryonic stem (ES) cells. Correctly targeted ES cells were transiently transfected with a cre expression plasmid to delete the neo cassette. Resulting ES cells contained multiple gene rearrangments; intact floxed-exons 2-3, intact floxed-neo cassette, or excision of both exons 2-3 and the neo cassette. Correctly targeted ES cells, containing only the floxed-exons 2-3, were injected into blastocysts and resulting chimeric males were bred with C57BL/6J females.

A second targeting vector was designed to insert a single a loxP-flanked neomycin resistance (neo) cassette upstream of exon 1 and a single loxP site downstream of exon 1 of the RAP-related protein-1b (Rap1b) gene. The construct was electroporated into 129S/SvEv-derived MM13 embryonic stem (ES) cells. Correctly targeted ES cells were transiently transfected with a cre expression plasmid to delete the neo cassette. Resulting ES cells contained multiple gene rearrangments; intact floxed-exon 1, intact floxed-neo cassette, or excision of both exon 1 and the neo cassette. Correctly targeted ES cells, containing only the floxed-exon 1, were injected into blastocysts and resulting chimeric males were bred with C57BL/6J females. Resulting offspring were bred to Rap1a floxed mice, and double floxed mice were maintained on a mixed C57BL/6J;129S background.

Upon arrival, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony.

Allele

Symbol: Rap1b^tm1Morz
Name: targeted mutation 1, Alexei Morozov
MGI accession ID: MGI:3777593
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Rap1b
Marker name: RAS related protein 1b
Chromosome: 10
Strain of origin: 129S/SvEv
Molecular note: A loxP-flanked neomycin selection cassette was inserted upstream of exon 1 with an additional loxP site inserted downstream of the exon. Transient expression of cre recombinase removed the neomycin selection cassette leaving exon 1 flanked by loxP sites. Correct targeted was confirmed through Southern blotting.

Allele

Symbol: Rap1a^tm1Morz
Name: targeted mutation 1, Alexei Morozov
MGI accession ID: MGI:3777591
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Rap1a
Marker name: RAS-related protein 1a
Chromosome: 3
Strain of origin: 129S/SvEv
Molecular note: A loxP site was inserted upstream of exon 2 and a loxP-flanked neomycin selection cassette was inserted downstream of exon 3. Transient expression of cre recombinase removed the neomycin cassette, leaving exons 2 and 3 flanked by loxP sites. Correct targeting was confirmed through Southern blots.