Male mice homozygous for this heat shock protein 2 knock out are infertile. This Hsp70-2 mutant strain may be useful in studies of infertility and meiosis.
Edward Mitch Eddy, NIEHS-NIH
Mice that are homozygous for the targeted mutation are viable, normal in size and do not display any gross physical or behavioral abnormalities. Homozygous male mice are infertile, homozygous female mice are fertile. No gene product (mRNA) is detected by Northern blot analysis of testis tissue from homozygous male animals. Immunohistochemical examination of seminiferous tubules does not detect protein gene product. Homozygous males have testes that weigh significantly less than testes from controls. Spermatogenesis in homozygotes is arrested in prophase of meiosis I with a reduced number of postmeitotic spermatids in seminiferous tubules, many with abnormal morphology, and no spermatozoa in the epididymis. Apoptosis of germ cells (late pachytene spermatocytes) in the testes is greatly increased in mutants. During backcrossing, the Y chromosome may not have been fixed to the C57BL/6J genetic background.
A targeting vector containing a PGK-Neo cassette was used to disrupt exon 2. The construct was electroporated into 129P2/OlaHsd derived E14TG2a/BK4 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts. The donating investigator reports that these mice were backcrossed to C57BL/6 for more than 20 generations (see SNP note below).
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, 3 of 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/6N genetic background.
|Allele Name||targeted mutation 1, David J Dix|
|Allele Type||Targeted (Null/Knockout)|
|Gene Symbol and Name||Hspa2, heat shock protein 2|
|Strain of Origin||129P2/OlaHsd|
|Molecular Note||The endogenous locus was disrupted by the insertion of a neomycin selection cassette inserted by homologous recombination. Transcript was undetected by Northern blot analysis of testicular tissue obtained from homozygous mutant mice. Immunostaining of testicular sections indicated an absence of normal protein in seminiferous tubules.|
|Mutations Made By|| |
Edward Mitch Eddy, NIEHS-NIH
When maintaining a live colony, these mice can be bred as heterozygotes. Homozygous males are infertile.
When using the B6.129P2-Hspa2tm1Dix/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #013584 in your Materials and Methods section.