title: Mapping of branchpoint nucleotides in mutant pre-mRNAs expressed in plant cells.
abstract: Pre-mRNA encoding rubisco activase in the Arabidopsis thaliana mutant rca contains a GU to AU change at the 5' splice site of intron 3 and this mutation results in accumulation of splicing intermediates bearing an incompletely processed intron. It has been demonstrated that one of the intermediates contains intron 3 in the form of a lariat and the branchpoint nucleotide has been mapped to the A residue at position -32 forming part of the sequence UUGAU. Analysis of a similar GU to AU 5' splice site mutation, present in a synthetic pre-mRNA context expressed in transfected protoplasts of Nicotiana plumbaginifolia, also suggests formation of lariats with branching occurring at A-31. A small fraction (approximately 10%) of this mutant pre-mRNA also underwent the second step of splicing. In addition to the consensus AG, an AU dinucleotide was used as splicing acceptor.
authors.affiliation: Friedrich Miescher-Institut, Basel, Switzerland.
authors.forename: H X
authors.initials: HX
authors.lastname: Liu
authors.forename: W
authors.initials: W
authors.lastname: Filipowicz
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002874:Chromosome Mapping; D017931:DNA Primers / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D007438:Introns; D008969:Molecular Sequence Data; D009154:Mutation; D010940:Plant Proteins; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D012322:RNA Precursors / Q000235:genetics* / Q000378:metabolism; D012326:RNA Splicing; D018749:RNA, Plant / Q000235:genetics* / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics; D014026:Nicotiana / Q000235:genetics
chemical_list: D017931:DNA Primers; D018744:DNA, Plant; D010940:Plant Proteins; D012322:RNA Precursors; D018749:RNA, Plant; C054765:rca protein, plant; D012273:Ribulose-Bisphosphate Carboxylase