Davis J F, Felder M R
Department of Biological Sciences, University of South Carolina, Columbia 29208.
J Biol Chem. 1993 Aug 5;268(22):16584-9.
A mouse cDNA clone for the ethanol-inducible cytochrome P-450 (P450IIE1) was obtained by screening a liver cDNA library with an oligonucleotide representing a consensus sequence found in the orthologous rat, human, and rabbit sequences. The protein sequence deduced from the cDNA sequence had an identity of 93% to rat, 81% to rabbit, and 76% to human orthologous sequences. The highest levels of P450IIE1 mRNA were found in liver of both sexes, and male kidney. Developmentally, C57BL/6 female liver P450IIE1 mRNA was detectable 1 day postpartum and reached steady-state levels in animals approximately 16-20 days of age. Kidney and adrenal gland P450IIE1 mRNA was found to be induced 25-50-fold and 4-fold by testosterone treatment, respectively, and the level in both tissues reached maximum levels between 12 h and 2 days after treatment. Nuclear run-on experiments demonstrated that testosterone treatment for 24-48 h resulted in a slight transcriptional activation of the P450IIE1 gene in the kidney. However, the increase in transcription rate was far below the increase in mRNA level, suggesting that much of the induction occurs by posttranscriptional mechanisms. This process requires the androgen receptor since mutant Tfm mice lacking receptor are not inducible.
通过用代表在大鼠、人类和兔子直系同源序列中发现的共有序列的寡核苷酸筛选肝脏cDNA文库，获得了乙醇诱导型细胞色素P - 450（P450IIE1）的小鼠cDNA克隆。从cDNA序列推导的蛋白质序列与大鼠的同源序列一致性为93%，与兔子的为81%，与人类的为76%。在雌雄两性的肝脏以及雄性肾脏中发现了最高水平的P450IIE1 mRNA。在发育过程中，C57BL / 6雌性肝脏中的P450IIE1 mRNA在产后1天即可检测到，并在约16 - 20日龄的动物中达到稳态水平。发现睾酮处理可分别使肾脏和肾上腺中的P450IIE1 mRNA诱导25 - 50倍和4倍，并且两个组织中的水平在处理后12小时至2天之间达到最高水平。细胞核连续转录实验表明，睾酮处理24 - 48小时会导致肾脏中P450IIE1基因轻微的转录激活。然而，转录速率的增加远低于mRNA水平的增加，这表明大部分诱导是通过转录后机制发生的。这个过程需要雄激素受体，因为缺乏受体的突变Tfm小鼠是不可诱导的。
