Klahre U, Hemmings-Mieszczak M, Filipowicz W
Friedrich Miescher-Institut, Basel, Switzerland.
Plant Mol Biol. 1995 Jun;28(3):569-74. doi: 10.1007/BF00020402.
We have previously characterized nuclear cDNA clones encoding two RNA binding proteins, CP-RBP30 and CP-RBP-31, which are targeted to chloroplasts in Nicotiana plumbaginifolia. In this report we describe the analysis of the 3'-untranslated regions (3'-UTRs) in 22 CP-RBP30 and 8 CP-RBP31 clones which reveals that mRNAs encoding both proteins have a very complex polyadenylation pattern. Fourteen distinct poly(A) sites were identified among CP-RBP30 clones and four sites among the CP-RBP31 clones. The authenticity of the sites was confirmed by RNase A/T1 mapping of N. plumbaginifolia RNA. CP-RBP30 provides an extreme example of the heterogeneity known to be a feature of mRNA polyadenylation in higher plants. Using PCR we have demonstrated that CP-RBP genes in N. plumbaginifolia and N. sylvestris, in addition to the previously described introns interrupting the coding region, contain an intron located in the 3' non-coding part of the gene. In the case of the CP-RBP31, we have identified one polyadenylation event occurring in this intron.
我们之前已经鉴定出编码两种RNA结合蛋白CP-RBP30和CP-RBP-31的核cDNA克隆，它们定位于白花烟草的叶绿体中。在本报告中，我们描述了对22个CP-RBP30和8个CP-RBP31克隆的3'非翻译区（3'-UTR）的分析，结果显示编码这两种蛋白的mRNA具有非常复杂的多聚腺苷酸化模式。在CP-RBP30克隆中鉴定出14个不同的聚腺苷酸化位点，在CP-RBP31克隆中鉴定出4个位点。通过对白花烟草RNA进行核糖核酸酶A/T1图谱分析，证实了这些位点的真实性。CP-RBP30提供了一个极端的例子，说明了已知是高等植物mRNA多聚腺苷酸化特征的异质性。利用聚合酶链反应（PCR），我们已经证明，除了先前描述的打断编码区的内含子外，白花烟草和林烟草中的CP-RBP基因在基因的3'非编码部分还含有一个内含子。就CP-RBP31而言，我们已经鉴定出在这个内含子中发生的一次多聚腺苷酸化事件。
