Open AccessSwitch in 3′ Splice Site Recognition between Exon Definition and Splicing Catalysis Is Important for Sex-lethalAutoregulation
Author(s) -
Luiz O. F. Penalva,
Marı́a José Lallena,
Juan Valcárcel
Publication year - 2001
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.21.6.1986-1996.2001
Subject(s) - exon , splice site mutation , rna splicing , biology , splice , intron , genetics , alternative splicing , exonic splicing enhancer , exon shuffling , spliceosome , exon skipping , splicing factor , gene , rna
Maintenance of female sexual identity in Drosophila melanogaster involves an autoregulatory loop in which the protein Sex-lethal (SXL) promotes skipping of exon 3 from its own pre-mRNA. We have used transient transfection of Drosophila Schneider cells to analyze the role of exon 3 splice sites in regulation. Our results indicate that exon 3 repression requires competition between the 5' splice sites of exons 2 and 3 but is independent of their relative strength. Two 3' splice site AG's precede exon 3. We report here that, while the distal site plays a critical role in defining the exon, the proximal site is preferentially used for the actual splicing reaction, arguing for a switch in 3' splice site recognition between exon definition and splicing catalysis. Remarkably, the presence of the two 3' splice sites is important for the efficient regulation by SXL, suggesting that SXL interferes with molecular events occurring between initial splice site communication across the exon and the splice site pairing that leads to intron removal.