Foldes R L, Hines R N, Ho K L, Shen M L, Nagel K B, Bresnick E
Arch Biochem Biophys. 1985 May 15;239(1):137-46. doi: 10.1016/0003-9861(85)90820-3.
Transcriptional control of 3-methylcholanthrene-dependent cytochrome P-450c nuclear RNA induction was directly observed in an in vitro rat liver nuclear transcription system. Mercurated and radiolabeled ribonucleotides were incorporated into nuclear RNA transcribed in vitro, which was then isolated using thiopropyl-Sepharose 6B affinity chromatography. Dot hybridization experiments were carried out using bacteriophage M13 subclones of pRSA57 (a cDNA clone for rat serum albumin), pEB339 (a cDNA clone for rat cytochrome P-450c), and clone 46 (a cDNA clone for mouse cytochrome P1-450). The results of these studies demonstrate that 3-methylcholanthrene does not significantly influence the transcription of the rat serum albumin gene, but does increase the transcription of the cytochrome P-450c gene. Nuclear RNA precursors to the cytochrome P-450c mRNA were characterized by Northern blot analysis. Clone 46 hybridized to nuclear RNA species of 6.7 and 4.0 kb, in addition to the 3.0-kb cytochrome P-450c mRNA. pA8 (a genomic clone for rat cytochrome P-450c), hybridized to the same nuclear RNA species in addition to nuclear RNA species of 4.3, 3.4, and 2.2 kb. M13pd15 (a genomic clone containing information for the first intron of the cytochrome P-450c gene) hybridized to nuclear RNA species of 6.7 and 4.3 kb. All of these nuclear RNA species are polyadenylated. The mRNA coding for cytochrome P-450c was induced maximally in hepatic nuclei at 3 h following 3-methylcholanthrene administration. Maximal accumulation of cytochrome P-450c mRNA in hepatic cytosol has been previously shown to occur at approximately 15 h following 3-methylcholanthrene administration (Bresnick, E., Brosseau, M., Levin, W., Reik, L., Ryan, D. E., and Thomas, P. E. (1981) Proc. Natl. Acad. Sci. USA 78, 4083-4087). These data implicate a possible role of nuclear RNA transport in the regulation of induction of cytochrome P-450c, although further investigations are indicated.
在体外大鼠肝细胞核转录系统中直接观察到了3-甲基胆蒽依赖性细胞色素P-450c核RNA诱导的转录调控。将汞化和放射性标记的核糖核苷酸掺入体外转录的核RNA中，然后使用硫丙基-琼脂糖凝胶6B亲和层析法进行分离。使用pRSA57（大鼠血清白蛋白的cDNA克隆）、pEB339（大鼠细胞色素P-450c的cDNA克隆）和克隆46（小鼠细胞色素P1-450的cDNA克隆）的噬菌体M13亚克隆进行点杂交实验。这些研究结果表明，3-甲基胆蒽不会显著影响大鼠血清白蛋白基因的转录，但会增加细胞色素P-450c基因的转录。通过Northern印迹分析对细胞色素P-450c mRNA的核RNA前体进行了表征。除了3.0 kb的细胞色素P-450c mRNA外，克隆46还与6.7和4.0 kb的核RNA种类杂交。pA8（大鼠细胞色素P-450c的基因组克隆）除了与4.3、3.4和2.2 kb的核RNA种类杂交外，还与相同的核RNA种类杂交。M13pd15（包含细胞色素P-450c基因第一个内含子信息的基因组克隆）与6.7和4.3 kb的核RNA种类杂交。所有这些核RNA种类都进行了多聚腺苷酸化。在给予3-甲基胆蒽后3小时，肝细胞核中编码细胞色素P-450c的mRNA诱导达到最大值。先前已表明，在给予3-甲基胆蒽后约15小时，肝细胞溶质中细胞色素P-450c mRNA的积累达到最大值（Bresnick, E., Brosseau, M., Levin, W., Reik, L., Ryan, D. E., and Thomas, P. E. (1981) Proc. Natl. Acad. Sci. USA 78, 4083 - 4087）。这些数据暗示核RNA转运在细胞色素P-450c诱导调控中可能发挥作用，尽管还需要进一步研究。
