Fleury A, Cloutier M, Ducharme L, Lefebvre A, LeHoux J, LeHoux J G
Department of Biochemistry, Faculty of Medicine, University of Sherbrooke, QC, Canada.
Endocr Res. 1996 Nov;22(4):515-20. doi: 10.1080/07435809609043740.
In this study, we report the cloning of a StAR cDNA from a hamster adrenal cDNA library. The library was screened using a PCR fragment specific for the hamster adrenal StAR cDNA. Several clones of different lengths were obtained and one of these was sequenced. Northern blotting analysis revealed the presence of the StAR mRNA in male and female adrenals, in tests and ovaries, but not in the liver or kidneys of either sex. Whole hamster adrenals revealed the presence of four mRNAs of 0.65, 1.7, 3.1 and 5.25 kb, respectively. In addition, ACTH regulates the expression of StAR mRNA in hamster adrenals. Indeed, when groups of hamsters were injected with ACTH and sacrificed at different times after treatment, only the 0.65 kb form of the StAR mRNA did not increase, whereas the other forms increased at varying levels. These results might suggest that the expression of the StAR protein in hamster adrenals depends upon different genes, different promoters, or different polyadenylation signal sites. In conclusion, these results indicate that in vivo, StAR is regulated by ACTH, suggesting the participation of this protein in controlling the transformation of cholesterol to pregnenolone, a key regulatory step in corticosteroidogenesis.
在本研究中，我们报道了从仓鼠肾上腺cDNA文库中克隆出类固醇生成急性调节蛋白（StAR）的cDNA。使用针对仓鼠肾上腺StAR cDNA的PCR片段对该文库进行筛选。获得了几个不同长度的克隆，并对其中一个进行了测序。Northern印迹分析显示，StAR mRNA存在于雄性和雌性肾上腺、睾丸和卵巢中，但不存在于两性的肝脏或肾脏中。完整的仓鼠肾上腺分别显示存在0.65、1.7、3.1和5.25 kb的四种mRNA。此外，促肾上腺皮质激素（ACTH）调节仓鼠肾上腺中StAR mRNA的表达。实际上，当给几组仓鼠注射ACTH并在治疗后的不同时间处死时，只有0.65 kb形式的StAR mRNA没有增加，而其他形式则有不同程度的增加。这些结果可能表明，仓鼠肾上腺中StAR蛋白的表达取决于不同的基因、不同的启动子或不同的聚腺苷酸化信号位点。总之，这些结果表明，在体内，StAR受ACTH调节，提示该蛋白参与控制胆固醇向孕烯醇酮的转化，这是皮质类固醇生成中的一个关键调节步骤。
