Intron creation and polyadenylation in maize are directed by AU-rich RNA.
Intron recognition in Angiosperms is hypothesized to require AU-rich motifs within introns. In this report we examined the role of AU-rich motifs in pre-mRNA processing. AU-rich segments of maize introns inserted near the single intron of the maize Bronze-2(Bz2) gene result in alternative splicing. Other insertions of AU-rich sequence in the Bz2 cDNA resulted in de novo intron creation using splice junctions at the edges of the AU-rich region. Surprisingly, the five AU-rich inserts that we tested also caused polyadenylation, even though none had been selected for that function in plants. Insertions of GC-rich sequence into Bz2 did not cause either splicing or polyadenylation. We propose that AU-rich motifs are a general signal for RNA processing in maize and that in the absence of a 5' splice site, polyadenylation is the default pathway.
Luehrsen
K R
KR
Department of Biological Sciences, Stanford University, California 94305-5020.
Walbot
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D017398:Alternative Splicing; D001482:Base Composition; D001483:Base Sequence; D017343:Genes, Plant; D007438:Introns; D008969:Molecular Sequence Data; D009843:Oligoribonucleotides / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics; D016133:Polymerase Chain Reaction; D012322:RNA Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism*; D018749:RNA, Plant / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism
D009843:Oligoribonucleotides; D010940:Plant Proteins; D012322:RNA Precursors; D012333:RNA, Messenger; D018749:RNA, Plant; C076971:BZ2 protein, Zea mays