The hypothyroid 3 Jackson spontaneous deletion provides a model for type 1 congenital nongoitrous hypothyroidism, with less impairment of fertility than that reported for other Tshr alleles.Read More +
Hypothyroid 3 Jackson homozygotes, like other thyroid stimulating hormone receptor mutants, are proportional dwarfs, approximately half the size of normal littermates. They are particularly fragile at around three weeks of age and many die at that time. Those that survive through wean age usually survive to adulthood and live a relatively normal lifespan, although there is some premature death in the adult population of homozygotes. On this background both male and female homozygotes have successfully bred with BALB/cByJ, with approximately half of the pairs set up producing litters, and the number of pups per litter was nearly normal. Heterozygous intercrosses produce fewer than the expected 25% homozygotes, indicative of some prenatal death.
The hypothyroid 3 Jackson mutation arose spontaneously in the CXB10/HiAJ-smrl/GrsrJ strain. This subline has had 3 generations of backcross-intercross breeding to BALB/cByJ by breeding homozygous ovary transplant hosts with BALB/cByJ then intercrossing the obligate heterozygous offspring. The smrl mutation has been bred out of this line. The fertility of homozygotes with this increased contribution of BALB/cByJ has improved fertility, with some homozygous males and some homozygous females successfully breeding without hormone supplements when mated to BALB/cByJ.
|Allele Name||hypothyroid 3 Jackson|
|Allele Type||Spontaneous (Not Specified)|
|Gene Symbol and Name||Tshr, thyroid stimulating hormone receptor|
|Strain of Origin||CXB10/HiAJ-Cacna1asmrl/GrsrJ|
|Molecular Note||This spontaneous 233 bp intragenic deletion is predicted to result in a frameshift, which, if translated, would introduce 11 novel amino acids beginning at amino acid 442 prior to a premature stop codon.|