title: Cryptic splicing sites are differentially utilized in vivo.
abstract: It has long been considered that cryptic splice sites are ignored by the splicing machinery in the context of intact genuine splice sites. In the present study, it is shown that cryptic splice sites are utilized in all circumstances, when the authentic site is intact, partially functional or completely abolished. Their use would therefore contribute to a background lack of fidelity in the context of the wild-type sequence. We also found that a mutation at the 5' splice site of beta-globin intron 1 accommodates multiple cryptic splicing pathways, including three previously reported pathways. Focusing on the two major cryptic 5' splice sites within beta-globin exon 1, we show that cryptic splice site selection ex vivo varies depending upon: (a) the cell stage of development during terminal erythroid differentiation; (b) the nature of the mutation at the authentic 5' splice site; and (c) the nature of the promoter. Finally, we found that the two major cryptic 5' splice sites are utilized with differential efficiencies in two siblings sharing the same beta-globin chromosome haplotype in the homozygous state. Collectively, these data suggest that intrinsic, sequence specific factors and cell genetic background factors both contribute to promote a subtle differential use of cryptic splice sites in vivo.
authors.affiliation: CNRS UMR 5534, Centre de Génétique Moléculaire et Cellulaire, Université Lyon 1, 16 rue Raphael Dubois, Villeurbanne Cedex, France.
authors.forename: Amel
authors.initials: A
authors.lastname: Haj Khelil
authors.forename: Mireille
authors.initials: M
authors.lastname: Deguillien
authors.forename: Madeleine
authors.initials: M
authors.lastname: Morinière
authors.forename: Jemni
authors.initials: J
authors.lastname: Ben Chibani
authors.forename: Faouzi
authors.initials: F
authors.lastname: Baklouti
mesh_terms: D002478:Cells, Cultured; D005091:Exons / Q000235:genetics; D005914:Globins / Q000235:genetics*; D006801:Humans; D007438:Introns / Q000235:genetics; D009154:Mutation; D011401:Promoter Regions, Genetic; D022821:RNA Splice Sites / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D022821:RNA Splice Sites; D005914:Globins