Mice homozygous for Ces1ce are viable and fertile and exhibit no apparent defect.
Ces1ce was discovered in a screen of progeny of triethylenemelamine (TEM) treated male mice for mutations at specific loci, but appears to have pre-existed in the male. The screen employed analysis of blood and kidney homogenates by "standard starch gel electrophoresis techniques" and focused on enzymes known to differ in electrophoretic mobility between the parental strains (DBA/2J and C57BL/6J). Ces1ce was initially thought to be a null allele, but characterization of homozygous F2 mice demonstrated presence of a faint band migrating between those of the parental strains, which was not perceived in the presence of either parental band. Thus, Ces1ce was shown to be a hypomorphic electrophoretic variant (Soares 1979).
Ces1ce was discovered in a specific-locus mutation screen of progeny of triethylenemelamine (TEM) mutagenized male DBA/2J mice, but appears to have been a pre-existing, spontaneous mutation. Although the TEM-treated parent was unavailable for genotyping, three lines of evidence suggest he was a heterozygous carrier of the mutation: 7 of 13 (54%) of his immediate offspring were heterozygous for Ces1ce; he was mated within 2 weeks after TEM treatment, so these progeny were generated from sperm that were either sperm or late spermatids when exposed, ruling out a clustering effect due to mutagenesis at the spermatogonial stage; and the seven Ces1ce/+ offspring occurred among litters of three dams (Soares 1979).
Mice of a strain/stock bearing Ces1ce, called ES-IE, were imported from Dr. Soares, then at NIEH, by Dr. Eva Eicher. The original stock was maintained by sister-brother inbreeding. In 1982, Ces1ce/Ces1ce males of this stock were bred to C57BL/6J females to produce embryos for cryopreservation. These heterozygous embryos were assigned Stock No. 000785. In 1995, mice were recovered from the cryopreserved embryos to generate an F2 generation, from which mice homozygous for both Ces1ce and a (nonagouti) were selected and bred to generate embryos for cryopreservation. These embryos, which are segregating for Tyrp1b and Myo5ad, were designated STOCK a/a Ces1ce/Ces1ce and retained Stock No. 000785.
In response to a request for a stock homozygous for both Ces1ce and H2d, mice were again recovered from cryopreservation and, as none of them carried H2d, they were outcrossed to DBA/2J. Doubly homozygous F2 progeny were selected as founders of STOCK Ces1ce/Ces1ce H2d/H2d (Stock No. 002974). In 1997, sperm from doubly homozygous males and ovaries from doubly homozygous females were cryopreserved.
|Allele Name||d variant|
|Gene Symbol and Name||H2, histocompatibility-2, MHC|
|Strain of Origin||various|
|General Note||The d variant has been observed in the following strains: DBA/2, DBA/2J BALB/c, BALB/cByJ, BALB/cJ, C57BLKS, NZB.|