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Mapping of branchpoint nucleotides in mutant pre‐mRNAs expressed in plant cells
Author(s) -
Liu HongXiang,
Filipowicz Witold
Publication year - 1996
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1996.09030381.x
Subject(s) - intron , rna splicing , mutant , splice , biology , microbiology and biotechnology , arabidopsis , messenger rna , nucleotide , genetics , precursor mrna , splice site mutation , rna , gene
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 UUG A U. 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.