维甲酸X受体γ基因敲除小鼠外观正常，且维甲酸X受体α+/-/维甲酸X受体β-/-/维甲酸X受体γ-/-复合突变小鼠可以存活。

Krezel W, Dupé V, Mark M, Dierich A, Kastner P, Chambon P

Institut de Génétique et de Biologie Moléculaire et Cellulaire, Collège de France, Illkirch, France.

Proc Natl Acad Sci U S A. 1996 Aug 20;93(17):9010-4. doi: 10.1073/pnas.93.17.9010.

The RXR gamma (RXR, retinoid X receptor) gene was disrupted in the mouse. Homozygous mutant mice developed normally and were indistinguishable from their RXR gamma +/- or wild-type littermates with respect to growth, fertility, viability, and apparent behavior in the animal facility. Moreover, RXR alpha -/-/RXR gamma -/- and RXR beta -/-/RXR gamma -/- mutant phenotypes were indistinguishable from those of RXR alpha -/- and RXR beta -/- mutants, respectively. Strikingly, RXR alpha +/-/RXR beta -/-/RXR gamma -/- triple mutants were viable. Thus, it appears that RXR gamma does not exert any essential function that cannot be performed by RXR alpha or RXR beta, and one copy of RXR alpha is sufficient to perform most of the functions of the RXRs.

维甲酸X受体γ（RXR）基因在小鼠中被破坏。纯合突变小鼠发育正常，在生长、生育力、活力以及在动物饲养设施中的明显行为方面，与它们的RXRγ+/-或野生型同窝小鼠没有区别。此外，RXRα-/-/RXRγ-/-和RXRβ-/-/RXRγ-/-突变表型分别与RXRα-/-和RXRβ-/-突变体的表型没有区别。令人惊讶的是，RXRα+/-/RXRβ-/-/RXRγ-/-三重突变体是有活力的。因此，似乎RXRγ不发挥任何RXRα或RXRβ无法执行的基本功能，并且一份RXRα拷贝就足以执行大多数RXRs的功能。