A combinatorial role for exon, intron and splice site sequences in splicing in maize.
Plant introns are typically AU-rich or U-rich, and this feature has been shown to be important for splicing. In maize, however, about 20% of the introns exceed 50% GC, and most of them are efficiently spliced. A series of constructs has been designed to analyze the cis requirements for splicing of the GC-rich Bz2 maize intron and two other GC-rich intron derivatives. By manipulating exon, intron and splice site sequences it is shown that exons can play an important role in intron definition: changes in exon sequences can increase splicing efficiency of a GC-rich intron from 17% to 86%. The relative difference, or base compositional contrast, in GC and U content between exon and intron sequences in the vicinity of splice sites, rather than the absolute base-content of the intron or exons, correlates with splicing efficiency. It is also shown that GC-rich intron constructs that are poorly spliced can be partially rescued by an improved 3' splice site.
Carle-Urioste
J C
JC
Department of Biological Sciences, Stanford University, CA 94305-5020, USA. pepecar@leland.stanford.edu
Brendel
V
V
Walbot
V
V
D001483:Base Sequence; D001665:Binding Sites; D005091:Exons; D007438:Introns; D008969:Molecular Sequence Data; D019151:Peptide Library; D012326:RNA Splicing; D003313:Zea mays / Q000235:genetics*
D019151:Peptide Library