Estrogen-induced ribonuclease activity in Xenopus liver.
Estrogen-induced ribonuclease activity in Xenopus liver.
复制标题
DOI：
10.1021/bi00107a018
复制
发表时间：
1991-10
期刊：
影响因子：
2.9
通讯作者：
R. Pastori;J. E. Moskaitis;Daniel R Schoenberg
中科院分区：
文献类型：
--
作者：
R. Pastori;J. E. Moskaitis;Daniel R Schoenberg
雌激素对雄性非洲爪哇造成编码mRNAs的细胞质不稳定，最明显的是白蛋白，但对编码细胞内蛋白如铁蛋白的mRNAs几乎没有影响。这份报告描述了在肝多聚体中发现的一种雌激素诱导的核糖核酸酶活性，它在体外降解白蛋白mRNA的速度是它降解铁蛋白mRNA的速度的4倍。当多聚体提取物与游离的肝脏RNA、分离的肝脏mRNPs或来自质粒载体的转录本孵育时，观察到这种不同的降解率。在对全长或5‘半白蛋白mRNA的转录本进行消化时，一致地观察到由一对约194个核苷酸组成的切割片段。该裂解片段的产生被用作研究多聚体核酸酶活性的一种方法。194个二倍体是由不依赖于镁(2+)的内切酶作用产生的。这将非洲爪哇肝脏的酶与体外降解组蛋白或c-myc mRNA的酶区分开来。它可以被400 mM的氯化钠或90摄氏度的加热灭活，但不能被胎盘核糖核酸酶抑制剂或N-乙基马来酰亚胺灭活。最后，多体核酸酶活性不会降解双链RNA。我们认为，雌激素诱导的核酸酶活性包含一种酶(S)，该酶可能介导激素调节的该组织基因稳定性的变化。
Estrogen administration to male Xenopus causes the cytoplasmic destabilization of the hepatic serum protein coding mRNAs, most notably, albumin, yet has little effect on mRNAs encoding intracellular proteins such as ferritin. This report describes an estrogen-inducible ribonuclease activity found in liver polysomes that degrades albumin mRNA 4 times faster in vitro than it degrades ferritin mRNA. This differential rate of degradation was observed upon incubation of polysome extract with free liver RNA, isolated liver mRNPs, or transcripts from plasmid vectors. A cleavage fragment consisting of a doublet of approximately 194 nucleotides in length was consistently observed upon digestion of transcripts for the full length or 5' half of albumin mRNA. The generation of this cleavage fragment was used as an assay to study properties of the polysome nuclease activity. The 194 doublet is produced by the action of a Mg(2+)-independent endonuclease. This distinguishes the Xenopus liver enzyme from the enzymes that degrade histone or c-myc mRNA in vitro. It is inactivated by 400 mM NaCl or heating at 90 degrees C, but not by placental ribonuclease inhibitor or N-ethylmaleimide. Finally, the polysomal nuclease activity does not degrade double-stranded RNA. We believe the estrogen-induced nuclease activity contains an enzyme(s) that may mediate hormone-regulated changes in mRNA stability in this tissue.