The mouse Duox2thyd mutation provides a genetic model for studying the specific function of DUOX2 in the thyroid gland and in other organ systems where it is hypothesized to play a role. The Duox2thyd mutation is mapped to chromosome 2 and identified as a T>G base pair change in exon 16 of Duox2. The mutation changes a highly conserved valine to glycine at amino acid position 674 (V674G) and was named "thyroid dyshormonogenesis" to signify a defect in thyroid hormone synthesis. Thyroid glands of mutant mice are goitrous and contain few normal follicles, and anterior pituitaries are dysplastic. Serum T(4) in homozygotes is about one-tenth the level of controls and is accompanied by a more than 100-fold increase in TSH. The weight of adult mutant mice is approximately half that of littermate controls, and serum IGF-I is reduced. The cochleae of mutant mice exhibit abnormalities characteristic of hypothyroidism, including a delayed formation of the inner sulcus and tunnel of Corti and an abnormally thickened tectorial membrane. Hearing thresholds of adult mutant mice are on average 50-60 decibels (dB) above those of controls.
The thyroid dyshormonogenesis mutation arose spontaneously in the B6.129-Tnfrsf1atm1Mak/J strain (stock #002818) at The Jackson Laboratory in 2000. After one backcross to C57BL/6J the offspring were intercrossed and the N1F2 progeny were genotyped for the Tnfrsf1atm1Mak mutation. Those lacking this targeted mutation were selected as breeders to continue the line, which has been maintained by breeding heterozygous males with hosts of homozygous ovarian transplantation. In 2007 this strain reached generation N1F6.
|Allele Name||thyroid dyshormonogenesis|
|Gene Symbol and Name||Duox2, dual oxidase 2|
|Strain of Origin||B6.129-Tnfrsf1atm1Mak/J|
|Molecular Note||A spontaneous T-to-G transition (A-to-C on forward strand) in exon 16 causes a change from a highly conserved valine to glycine at amino acid position 674 (p.V674G).|