B6;129S1-Notch4^tm1Grid/J

Stock number: 010544
Product name: Notch4^-
Research areas: Developmental Biology Research, Research Tools

Description

These Notch4^tm1Grid knock-out mice may be useful in studies of the Notch pathway during development.

Detailed description

Mice that are homozygous for the targeted mutation are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. No gene product (mRNA) is detected by RT-PCR analysis of lung and kidney tissue from homozygous adult animals, and in situ hybridization of homozygous embryos. Homozygotes exhibit a slightly elevated systolic blood pressure.

Development

A targeting vector containing neomycin resistance and herpes simplex virus thymidine kinase genes was used to delete 1.0kb of sequence containing exons 21 and 22, which encodes part of the extracellular domain. The construct was electroporated into 129S1/Sv-Oca2⁺ Tyr⁺ Kitl⁺ derived CJ7 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6J blastocysts. The resulting chimeric animals were crossed to C57BL/6J mice. Heterozyotes were crossed to generate homozygotes. The mice were bred once to C57BL/6J mice to establish the distribution colony.

Allele

Symbol: Notch4^tm1Grid
Name: targeted mutation 1, Tom Gridley
MGI accession ID: MGI:1929139
Generation method: Targeted
Marker symbol: Notch4
Marker name: notch 4
Chromosome: 17
Strain of origin: 129S1/Sv-Oca2⁺ Tyr⁺ Kitl⁺
Molecular note: This allele carries a deletion of 1.0 kb of sequence containing exons 21 and 22, which encode part of the extracellular domain of the protein. Subsequent analysis presented in J:212472 revealed that this allele is not null as it overexpresses a truncated transcript encoding most of the extracellular domain of the receptor, including all 29 EGF-like repeats and the Lin12-Notch repeats LNR-A and LNR-B followed by 10 amino acids. The predicted protein lacks the third LNR repeat (LNR-C), heterodimerisation domain, transmembrane domain, and the intracellular domain. Northern blot analysis using a probe upstream of the targeting site containing exons 1 to 5 indicated that Notch4 transcripts are overexpressed 2.6-fold in homozygous and 1.7-fold in heterozygous neonatal lung tissue. Whole-mount immunofluorescence detected strong NOTCH4 reactivity in the developing arteries of P5 homozygous mutant retinas, with heterozygous retinas showing intermediate expression. Importantly, the truncated receptor retains the capacity to inhibit NOTCH1 signaling when expressed in cis, raising the possibility that reported phenotypes may not be due to loss of NOTCH4 function.