129-Crmp1^tm1Pako Dpysl4^tm1Ttq/J

Stock number: 016927
Research areas: Developmental Biology Research, Neurobiology Research, Research Tools

Description

In this strain an IRES-lacZ-neo cassette replaces part of exon 4 of the Crmp1 gene, and a second IRES-lacZ-neo cassette replaces exon 3 of the Dpysl4 gene. This strain may be useful for studying nervous system developmental disorders.

Detailed description

In this strain an IRES-lacZ-neo cassette replaces part of exon 4 of the collapsin response mediator protein 1 (Crmp1) gene, and a second IRES-lacZ-neo cassette replaces exon 3 of the dihydropyrimidinase-like 4 (Dpysl4 or Crmp3) gene. Double homozygotes are viable and fertile. CRMP-1 and CRMP-3 are members of a family of phosphoproteins that are involved in dendritic length and branching, semaphorin signaling pathway, growth cone collapse, and neurite extension after binding with tubulin heterodimers. CRMP-1 is expressed during brain development in the cerebellum, olfactory bulb, hypothalamus, and retina, but is restricted mainly to the hippocampus and olfactory bulb in adults. CRMP-1 single knockout (KO) mice exhibit a decrease in granule cell proliferation, apoptosis, and migration. Also radial migration of cortical neurons is delayed. CRMP-3 is also expressed during brain development, but is restricted to the hippocampus, pontine nuclei, and olivary complex in adults. Deficiency in CRMP-3 is also found in Down Syndrome, where it leads to alterations in spine morphology, dendritic arborization, and abnormal neuronal orientation. CRMP-3 KO mice exhibit abnormal dendrite and spine morphogenesis in the hippocampus and aberration of long term potentiation, and an increase in number of thick dendrites in the stratum oriens. Apical and basal dendrites in the CRMP-3 knockout mice show reductions in length and branching. Since CRMP proteins are capable of forming homodimers and heterodimers, there may be an additive neural effect conveyed in this double knockout strain. This strain may be useful for studying nervous system developmental disorders.

Development

A targeting vector was designed to replace part of exon 4 of the collapsin response mediator protein 1 (Crmp1) gene with an internal ribosome entry site (IRES)-β-galactosidase (lacZ) followed by a neomycin resistance cassette. The construct was electroporated into (129X1/SvJ x 129S1/Sv)F1-Kitl⁺-derived R1 embryonic stem (ES) cells. Correctly targeted ES cells were aggregated with ICR morulae and the resulting chimeric males were bred with ICR females for germline transmission. A chimeric male was bred to a 129/SvE females, and the offspring were then subsequently backcrossed to 129/SvE for at least 7 generations to generate a colony of Crmp1^-/- mice.

Another targeting vector was designed to replace exon 3 of the dihydropyrimidinase-like 4 (Dpysl4 or Crmp3) gene with an internal ribosome entry site (IRES)-β-galactosidase (lacZ) followed by a neomycin resistance cassette. The construct was electroporated into (129X1/SvJ x 129S1/Sv)F1-Kitl⁺-derived R1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and the resulting chimeric males were bred to 129/SvE females. The resulting offspring were then backcrossed to 129/SvE for at least 7 generations to generate a colony of Crmp3^-/- mice.

Homozygous Crmp1^-/- mice were then crossed with Crmp3^-/- to produce a double knockout mutant strain. Upon arrival at The Jackson Laboratory, mice were bred to 129S1/SvImJ (Stock No. 002448) for at least one generation.

Allele

Symbol: Crmp1^tm1Pako
Name: targeted mutation 1, Pappachan Kolattukudy
MGI accession ID: MGI:3701338
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Marker symbol: Crmp1
Marker name: collapsin response mediator protein 1
Chromosome: 5
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Expressed genes: lacZ,beta-galactosidase,E. coli
Site of expression: Crmp1 is normally expressed during brain development in the cerebellum, olfactory bulb, hypothalamus, and retina, but is restricted mainly to the hippocampus and olfactory bulb in adults.
Molecular note: An IRES-LacZ-neo cassette was inserted to replace part of exon 4. Western blot analysis confirmed the absence of protein.

Allele

Symbol: Dpysl4^tm1Ttq
Name: targeted mutation 1, Tam T Quach
MGI accession ID: MGI:3790672
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Marker symbol: Dpysl4
Marker name: dihydropyrimidinase-like 4
Chromosome: 7
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Expressed genes: lacZ,beta-galactosidase,E. coli
Site of expression: Dpysl4 KO mice exhibit abnormal dendrite and spine morphogenesis in the hippocampus and aberration of long term potentiation, and an increase in number of thick dendrites in the stratum oriens. Apical and basal dendrites in the Dpysl4 knockout mice show reductions in length and branching.
Molecular note: Exon 3 was replaced with an IRES-lacZ-neo cassette. The absence of protein product was confirmed by western blot analysis on hippocampus extracts. This is a null allele and a reporter allele.