[HTML][HTML] Four Core Genotypes mouse model: localization of the Sry transgene and bioassay for testicular hormone levels

Y Itoh, R Mackie, K Kampf, S Domadia, JD Brown… - BMC research …, 2015 - Springer
Y Itoh, R Mackie, K Kampf, S Domadia, JD Brown, R O'Neill, AP Arnold
BMC research notes, 2015Springer
Background The “four core genotypes”(FCG) mouse model has emerged as a major model
testing if sex differences in phenotypes are caused by sex chromosome complement (XX vs.
XY) or gonadal hormones or both. The model involves deletion of the testis-determining
gene Sry from the Y chromosome and insertion of an Sry transgene onto an autosome. It
produces XX and XY mice with testes, and XX and XY mice with ovaries, so that XX and XY
mice with the same type of gonad can be compared to assess phenotypic effects of sex …
Background
The “four core genotypes” (FCG) mouse model has emerged as a major model testing if sex differences in phenotypes are caused by sex chromosome complement (XX vs. XY) or gonadal hormones or both. The model involves deletion of the testis-determining gene Sry from the Y chromosome and insertion of an Sry transgene onto an autosome. It produces XX and XY mice with testes, and XX and XY mice with ovaries, so that XX and XY mice with the same type of gonad can be compared to assess phenotypic effects of sex chromosome complement in cells and tissues.
Findings
We used PCR to amplify the Sry transgene and adjacent genomic sequences, to resolve the location of the Sry transgene to chromosome 3 and confirmed this location by fluorescence in situ hybridization (FISH) of the Sry construct to metaphase chromosomes. Using quantitative PCR, we estimate that 12–14 copies of the transgene were inserted. The anogenital distance (AGD) of FCG pups at 27–29 days after birth was not different in XX vs. XY males, or XX vs. XY females, suggesting that differences between XX and XY mice with the same type of gonad are not caused by difference in prenatal androgen levels.
Conclusion
The Sry transgene in FCG mice is present in multiple copies at one locus on chromosome 3, which does not interrupt known genes. XX and XY mice with the same type of gonad do not show evidence of different androgen levels prenatally.
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