Ryffel G U, Wyler T, Muellener D B, Weber R
Cell. 1980 Jan;19(1):53-61. doi: 10.1016/0092-8674(80)90387-6.
To understand the mechanism of estrogen-induced activation of the vitellogenin genes in the liver of Xenopus, it is essential to characterize the transcriptional products of these genes. In this paper we describe large nuclear RNAs containing vitellogenin mRNA sequences as revealed by hybridization of cloned vitellogenin cDNAs to nuclear RNA separated on agarose gels. Putative vitellogenin mRNA precursors, which are recovered as poly(A)-containing RNA, have been identified for the four known vitellogenin mRNAs. From electron microscopic analysis of R loops, prepared between enriched mRNA precursors and cDNA specific for the A1 vitellogenin mRNA, we conclude that the precursor molecules contain sequences complementary to vitellogenin mRNA which are interrupted by additional RNA segments probably representing transcribed introns. Within the 3.7 kb of the 3' end of the A1 vitellogenin mRNA we have discovered seven large and at least five small transcribed introns. Some of the R loops have been found to contain only a few transcribed introns, and we assume that they represent processing intermediates. Comparison of these putative intermediates suggests that the splicing order of different introns does not follow a single pathway.
为了解雌激素诱导非洲爪蟾肝脏中卵黄蛋白原基因激活的机制，对这些基因的转录产物进行表征至关重要。在本文中，我们描述了通过将克隆的卵黄蛋白原cDNA与在琼脂糖凝胶上分离的核RNA杂交所揭示的含有卵黄蛋白原mRNA序列的大核RNA。已针对四种已知的卵黄蛋白原mRNA鉴定出作为含poly(A) RNA回收的推定卵黄蛋白原mRNA前体。通过对富集的mRNA前体与A1卵黄蛋白原mRNA特异性cDNA之间制备的R环进行电子显微镜分析，我们得出结论，前体分子包含与卵黄蛋白原mRNA互补的序列，这些序列被可能代表转录内含子的额外RNA片段打断。在A1卵黄蛋白原mRNA 3'端的3.7 kb范围内，我们发现了七个大的和至少五个小的转录内含子。已发现一些R环仅包含少数转录内含子，我们认为它们代表加工中间体。对这些推定中间体的比较表明，不同内含子的剪接顺序并不遵循单一途径。
