This Gja5 (Cx40 ) knockout strain exhibits multiple defects of the cardiovascular system. These mice may be suitable for use in studies related to inter-endothelial communication and skeletal development.
David L Paul, Harvard Medical School
Alexander Simon, University of Arizona
The Gja5 gene encodes an intercellular channel forming protein, also known as Connexin 40, which functions as a component of gap junctions. These mice carry a knock out mutation of the Gja5 gene in which a PGK-NEO cassette replaces the single coding exon.
No gene product (mRNA or protein) is detected by RT-PCR of heart tissue from homozygous E11.5 embryos, immunohistochemical analysis of heart tissue, immunocytochemical analysis of arterial endothelium, or Western blot analysis of aortic endothelial lysates and whole aorta membranes from homozygotes.
Homozygotes exhibit defects of the cardiovascular system including: cardiac conduction abnormalities, impaired interendothelial communication, impaired propagation of arteriole vasomotor responses, hypertension with elevated renin levels, developmental cardiac malformations, compromised post-ischemic recovery (hindlimb), and reduced platelet function. In addition, malformation of axial and appendicular bones is observed. Homozygotes are fertile, but it should be noted that the Donating Investigator reports that homozygotes have a slightly reduced viability compared to heterozygotes.
During backcrossing, the Y chromosome may not have been fixed to the C57BL/6 genetic background.
A targeting vector containing a PGK-NEO cassette was used to disrupt the single coding exon of the gene. The construct was electroporated into 129S4/SvJae derived J1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were tested for germline transmission. The mice were then backcrossed to C57BL/6 for 6 generations (see SNP note below). During backcrossing, the Y chromosome may not have been fixed to the C57BL/6 genetic background. Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony.
A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. While the 27 markers throughout the genome suggested a C57BL/6 genetic background, all 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a C57BL/6J ; C57BL/6N genetic background.
|Allele Name||targeted mutation 1, David L Paul|
|Allele Type||Targeted (Null/Knockout)|
|Gene Symbol and Name||Gja5, gap junction protein, alpha 5|
|Strain of Origin||129S4/SvJae|
|Molecular Note||The single coding exon of the gene was deleted and replaced with a PGK-neo cassette via homologous recombination. Absence of gene expression was confirmed by immunohistochemical analysis of frozen heart sections from homozygous mutant animals.|
When maintaining a live colony, these mice can be bred as homozygotes. The Donating Investigator reports that homozygotes have a slightly reduced viability compared to heterozygotes.
When using the B6.129S4-Gja5tm1Paul/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #025697 in your Materials and Methods section.