FVB.129S1(B6)-Notch4^tm1Grid/MshaJ

Stock number: 023808
Product name: Notch4^d1
Strain synonyms: Notch4-
Research areas: Developmental Biology Research

Description

Notch4^d1 knockout mice exhibit a slightly elevated systolic blood pressure. They may be useful in studies of the Notch pathway during development.

Detailed description

Homozygous mice exhibit a slightly elevated systolic blood pressure, are viable, fertile and normal in size. No gene product (mRNA) is detected by RT-PCR analysis of lung and kidney tissue from homozygous adult animals. Similarly, no transcripts are detected via in situ hybridization analysis of homozygous embryos.

In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. It should be noted that the phenotype of these FVB-congenic mice could vary from that originally described on a B6;129S1 genetic background. We may modify the strain description if necessary as published results become available.

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. These mice arrived at The Jackson Laboratory as Stock No. 010544.

After obtaining them, Dr. Madhulika Sharma from The University of Kansas Medical Center crossed these mice to B6;129S1-Notch3^tm1Grid/J mice (Stock No. 010547) and double mutants were bred to FVB/NJ mice for at least six generations. Backcrossed mice were sent to The Jackson Laboratory, where they were bred to FVB/NJ inbred mice (Stock No. 001800) for at least one generation to establish Stock No. 023808. The Notch3^tm1Grid allele was bred out and maintained as Stock No. 023807.

Allele

Symbol: Notch4^tm1Grid
Name: targeted mutation 1, Tom Gridley
MGI accession ID: MGI:1929139
Generation method: Targeted
Synonyms: Notch4^-; Notch4^d1
Marker symbol: Notch4
Marker name: notch 4
Marker synonyms: INT3; Int-3; N4
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.