These Tet1 knock-out mice may be useful in studies of embryonic cell pluripotency and development.
Rudolf Jaenisch, Whitehead Institute, Massachusetts Institute of Technology
Mice that are heterozygous for the targeted mutation are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. No gene product (mRNA carrying exon 4 or protein) is detected by RT-PCR or Western blot analysis of embryonic stem cells homozygous for the targeted mutation. Some residual full-length transcript lacking exon 4 is detected. No truncated protein is detected by Western blot. mESC from homozygotes have a reduced level of 5-hydroxymethylcytosine (5hmC). Although homozygotes are viable, at birth, 75% of homozygotes have a smaller body size than wildtype controls. Homozygous embryos at E12.5 have fewer tail somite pairs than wildtype controls. Homozygous crosses produce very few pups.
A targeting vector containing a FRT site flanked NEO cassette with a downstream loxP site was inserted upstream of exon 5. A second loxP site was inserted upstream of exon 4. The construct was electroporated into (C57BL/6 x 129S4/SvJae)F1 derived V6.5 embryonic stem (ES) cells, which were transiently transfected with a Cre recombinase vector to remove the selection cassette. Correctly targeted ES cells that no longer contained exon 4 were injected into recipient blastocysts. The resulting male chimeric animals were crossed to C57BL/6 female mice. Heterozygotes were intercrossed to generate homozygotes. Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony.
|Allele Name||targeted mutation 1.1, Rudolf Jaenisch|
|Allele Type||Targeted (Null/Knockout)|
|Gene Symbol and Name||Tet1, tet methylcytosine dioxygenase 1|
|Strain of Origin||(C57BL/6 x 129S4/SvJae)F1|
|Molecular Note||A targeting vector containing a FRT site flanked neo cassette with a downstream loxP site was inserted upstream of exon 5. A second loxP site was inserted upstream of exon 4. Cre-mediated recombination removed the neo cassette and exon 4. The absence of protein expression was confirmed by western blot analysis on mouse embryonic fibroblasts.|
When maintaining a live colony, these mice can be bred as heterozygotes. Homozygous crosses produce very few pups.
When using the Tet1 knock-out mouse strain in a publication, please cite the originating article(s) and include JAX stock #017358 in your Materials and Methods section.