Brock M L, Shapiro D J
Cell. 1983 Aug;34(1):207-14. doi: 10.1016/0092-8674(83)90151-4.
We have demonstrated, by DNA excess filter hybridizations to pulse-labeled cell RNA, that estrogen selectively stabilizes Xenopus liver vitellogenin mRNA against cytoplasmic degradation. The half-life of vitellogenin mRNA is approximately 3 weeks in the presence of estrogen and 16 hr after estrogen is withdrawn from the culture medium. Total poly(A) mRNA exhibits the same half-life (16 hr) in the presence or absence of estrogen. The rapid cytoplasmic degradation of vitellogenin mRNA in the absence of estrogen is fully reversible upon restimulation with estrogen, indicating that nuclear modification of vitellogenin RNA transcripts is not responsible for their stability. Intermediate levels of vitellogenin mRNA stability and changes in the relative rate of vitellogenin gene transcription are not observed late in estrogen induction, when vitellogenin mRNA levels plateau. Instead, Xenopus liver cells achieve fine control over the level of vitellogenin mRNA through down-regulation of the overall rate of total nuclear RNA synthesis.
通过对脉冲标记的细胞RNA进行DNA过量滤膜杂交，我们已经证明，雌激素可选择性地稳定非洲爪蟾肝脏卵黄蛋白原mRNA，使其免受细胞质降解。在有雌激素存在的情况下，卵黄蛋白原mRNA的半衰期约为3周，而从培养基中撤除雌激素后，其半衰期为16小时。无论有无雌激素存在，总的聚腺苷酸mRNA都表现出相同的半衰期（16小时）。在没有雌激素的情况下，卵黄蛋白原mRNA在细胞质中的快速降解在重新用雌激素刺激后是完全可逆的，这表明卵黄蛋白原RNA转录本的核修饰与其稳定性无关。在雌激素诱导后期，当卵黄蛋白原mRNA水平达到平稳时，未观察到卵黄蛋白原mRNA稳定性的中间水平以及卵黄蛋白原基因转录相对速率的变化。相反，非洲爪蟾肝细胞通过下调总的核RNA合成的整体速率，对卵黄蛋白原mRNA的水平实现了精细控制。
