Extreme heterogeneity of polyadenylation sites in mRNAs encoding chloroplast RNA-binding proteins in Nicotiana plumbaginifolia

• Published in: Plant molecular biology Vol. 28; no. 3; p. 569
• Main Authors: Klahre, U. (Friedrich Miescher-Inst., Basel (Switzerland)), Hemmings-Mieszczak, M, Filipowicz, W
• Format: Journal Article
• Language: English
• Published: Netherlands 01.06.1995
• Subjects: ARN MENSAJERO; ARN MESSAGER; Base Sequence; CHLOROPLASTE; CHLOROPLASTS; Chloroplasts - metabolism; CLOROPLASTO; CODE GENETIQUE; CODIGO GENETICO; DNA, Complementary; GENETIC CODE; Hydrolysis; MESSENGER RNA; Molecular Sequence Data; NICOTIANA; Nicotiana - genetics; Nicotiana - metabolism; Plants, Toxic; Poly A - metabolism; PROTEINAS; PROTEINE; PROTEINS; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Plant - genetics; RNA, Plant - metabolism; RNA-Binding Proteins - genetics; RNA-Binding Proteins - metabolism
• ISSN: 0167-4412; 1573-5028
• 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.