In healthy cartilage of Frzb-/ mice, four genes were consistently expressed at lower levels than in the wild-type mice: Ctnnb1, Ctbp1, Fosl1 and Myc.
In addition to the over-expression of chaperone activator and chaperone protein genes in the Tg mice, six genes involved in protein degradation were also part of the GO category of Protein mis-folding correction & degradation.
In the vertebrate lineage alone the number of dmrt genes varies widely: eight genes (dmrt1-8) in human and mouse, five genes (dmrt1-5) in fish, two genes (dmrt1 and dmrt4) in Xenopus and three genes (dmrt1-3) in chick [31], [32].
Group II contains genes from zebrafish (OlfCc1), goldfish (receptor 5.3), fugu (735220), and mouse (three genes closely related to and including V2R2).
In mice, only two genes had lost multiple introns (Table 2).
Since the phenotype shows resemblance to the integrin β6 -/- knockout phenotype seen in mice, the two genes encoding the two subunits of integrin αvβ6, i.e. ITGB6 and ITGAV, were considered candidate genes for this trait.
But mice have two genes, one expressed in the kidney and one expressed only in the salivary gland, where the enzyme is probably more important as a chemical signal (25).
To investigate this, we comparatively analyzed Dact gene expression in animals with the most divergent complements of Dact genes: mouse (three Dact genes), chicken (two Dact genes), Xenopus (two dact genes, but both belong to the dact 1/3 group) versus zebrafish (six dact genes).
In humans and mice, three GLIS genes (GLIS1, GLIS2 and GLIS3) have been found [38] [40], [65].
Whereas in humans, the multidrug resistance 1 (MDR1) gene encodes for P-gp in mice and rats two genes (Mdr1a and Mdr1b) encode for two subtypes of P-gp that together perform the same function as human P-gp [5].
