Pastori R L, Moskaitis J E, Buzek S W, Schoenberg D R
Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799.
J Steroid Biochem Mol Biol. 1992 Aug;42(7):649-57. doi: 10.1016/0960-0760(92)90105-r.
Estrogen destabilizes transferrin mRNA in male Xenopus liver in the same manner as observed for albumin and gamma-fibrinogen. The present study examined estrogen regulation of transferrin gene expression in female Xenopus liver and oviduct. In female Xenopus liver estrogen causes the same enhanced degradation of transferrin mRNA from the cytoplasm as seen in males. In contrast, transferrin is induced 3- to 4-fold in both oviduct nuclear and cytoplasmic RNA. The similar increase in transferrin RNA in both preparations suggests a transcriptional mechanism is responsible for this stimulation. Therefore, transferrin expression is differentially regulated in these tissues by the same hormone. Previous experiments showed that Xenopus serum albumin mRNA has a very short (17 residue) poly(A) tail that may play a role in its hormone-regulated instability. Transferrin mRNA has a similarly short poly(A) tail in liver of both male and female Xenopus. Estrogen has no effect on transferrin polyadenylation in liver. Similarly short poly(A) is found on transferrin mRNA from estrogen-deprived oviducts in explant culture. However, addition of estradiol to the medium results in the appearance of a 50-200 nucleotide poly(A) concurrent with induction. Therefore, transferrin mRNA is differentially polyadenylated in Xenopus liver and oviduct. In the latter tissue polyadenylation is under hormonal control.
雌激素使雄性非洲爪蟾肝脏中的转铁蛋白mRNA不稳定，其方式与白蛋白和γ-纤维蛋白原相同。本研究检测了雌激素对雌性非洲爪蟾肝脏和输卵管中转铁蛋白基因表达的调控。在雌性非洲爪蟾肝脏中，雌激素导致细胞质中转铁蛋白mRNA的降解增强，这与在雄性中的情况相同。相反，在输卵管的核RNA和细胞质RNA中，转铁蛋白被诱导增加3至4倍。两种制剂中转铁蛋白RNA的类似增加表明转录机制是这种刺激的原因。因此，相同的激素在这些组织中对转铁蛋白表达进行差异调节。先前的实验表明，非洲爪蟾血清白蛋白mRNA具有非常短（17个残基）的聚腺苷酸尾，这可能在其激素调节的不稳定性中起作用。在雄性和雌性非洲爪蟾的肝脏中，转铁蛋白mRNA也有类似的短聚腺苷酸尾。雌激素对肝脏中转铁蛋白的聚腺苷酸化没有影响。在体外培养中，来自雌激素缺乏的输卵管的转铁蛋白mRNA上也发现了类似的短聚腺苷酸。然而，向培养基中添加雌二醇会导致出现50 - 200个核苷酸的聚腺苷酸，同时伴随着诱导作用。因此，非洲爪蟾肝脏和输卵管中转铁蛋白mRNA的聚腺苷酸化存在差异。在后者组织中，聚腺苷酸化受激素控制。
