Mano H, Ozawa T, Takeyama K, Yoshizawa Y, Kojima R, Kato S, Masushige S
Department of Agricultural Chemistry, Faculty of Agriculture, Tokyo University of Agriculture, Japan.
Biochem Biophys Res Commun. 1993 Mar 31;191(3):943-9. doi: 10.1006/bbrc.1993.1308.
Gene expression of three nuclear retinoid X receptors (RXR alpha, beta and gamma) was examined by Northern blot analysis in various rat tissues. The RXR alpha mRNA (5.5 kb) was detected in most tissues and particularly expressed at a high level in the liver. The RXR beta transcripts (2.4 and 3.0 kb) were expressed ubiquitously, and particularly at high levels in the brain and testis. In the liver, heart, kidney and lung, the RXR gamma mRNA (2.0 kb) was specifically detected. Furthermore, we examined the effect of retinoid, vitamin D and thyroid hormone status on the gene expression of RXR alpha, beta and gamma. Though retinoid and vitamin D did not affect the mRNA levels of three RXRs, the mRNA levels of two genes were controlled by thyroid hormone. Namely, positive (RXR beta) and negative (RXR gamma) regulations by thyroid hormone were observed with no effect on the gene expression of RXR alpha. These results suggest that thyroid hormone might affect the signal transduction of retinoid, vitamin D and thyroid hormone by changing RXR levels.
通过Northern印迹分析检测了三种核视黄酸X受体（RXRα、β和γ）在各种大鼠组织中的基因表达。在大多数组织中均检测到RXRα mRNA（5.5 kb），在肝脏中尤其高水平表达。RXRβ转录本（2.4和3.0 kb）广泛表达，在脑和睾丸中尤其高水平表达。在肝脏、心脏、肾脏和肺中特异性检测到RXRγ mRNA（2.0 kb）。此外，我们研究了视黄酸、维生素D和甲状腺激素状态对RXRα、β和γ基因表达的影响。尽管视黄酸和维生素D不影响三种RXR的mRNA水平，但两个基因的mRNA水平受甲状腺激素调控。具体而言，观察到甲状腺激素对RXRβ呈正向调控，对RXRγ呈负向调控，而对RXRα的基因表达无影响。这些结果表明，甲状腺激素可能通过改变RXR水平影响视黄酸、维生素D和甲状腺激素的信号转导。
