Arabian A, Grover J, Barré M G, Delvin E E
Genetics Unit, Shriners Hospital, Montreal, Quebec, Canada.
J Steroid Biochem Mol Biol. 1993 Jun;45(6):513-6. doi: 10.1016/0960-0760(93)90167-u.
Total RNA was isolated from kidneys of Sprague-Dawley rats. Oligo (dT)-primed single-stranded cDNA was obtained by the reverse transcriptase reaction from which a 285 bp cDNA probe coding for 25-hydroxyvitamin D3-24-hydroxylase [25(OH)D3-24-OHase] was generated by the polymerase chain reaction. Northern blotting performed with kidney poly (A)+ RNA isolated from rats (1) fed a standard diet, (2) depleted in D3 and hypocalcemic, and (3) fed a standard diet and injected intraperitoneally with 50,000 IU of vitamin D3 for 5 days showed that the transcript for 24-OHase was weakly expressed in control, and highly induced in vitamin D3-treated animals. No transcript could be elicited in vitamin D-depleted hypocalcemic animals in which 25(OH)D3-1 alpha-OHase was maximally induced. The data show that 24-OHase is independently regulated of 1 alpha-OHase, strongly suggestive of the enzymes being encoded by two distinct genes.
从斯普拉格-道利大鼠的肾脏中分离出总RNA。通过逆转录酶反应获得寡聚（dT）引物的单链cDNA，利用聚合酶链反应从该单链cDNA中生成一个编码25-羟维生素D3-24-羟化酶[25(OH)D3-24-OHase]的285 bp cDNA探针。用从以下三组大鼠中分离得到的肾脏多聚（A）+RNA进行Northern印迹分析：（1）喂食标准饮食的大鼠；（2）维生素D3缺乏且血钙过低的大鼠；（3）喂食标准饮食并腹腔注射50,000 IU维生素D3持续5天的大鼠。结果显示，24-羟化酶的转录本在对照组中表达较弱，而在维生素D3处理的动物中高度诱导表达。在维生素D缺乏且血钙过低的动物中，25(OH)D3-1α-羟化酶被最大程度诱导，但未检测到24-羟化酶的转录本。数据表明，24-羟化酶的表达独立于1α-羟化酶，强烈提示这两种酶由两个不同的基因编码。
