title: The c.1275A>G putative chronic pancreatitis-associated synonymous polymorphism in the glycoprotein 2 (GP2) gene decreases exon 9 inclusion.
abstract: We have recently found that a common synonymous single nucleotide polymorphism (SNP), c.1275A>G, in exon 9 of the glycoprotein 2 (GP2) gene was significantly underrepresented in French idiopathic chronic pancreatitis patients 20years old or younger at disease onset than in the control population. To further investigate to this preliminary genetic finding, we characterized the functionality of c.1275A>G in the context of a minigene system. Bioinformatics analysis predicted that c.1275A>G could lead to disruption/generation of exonic splicing enhancer hexamers within exon 9 of the GP2 gene. Minigene analysis revealed that both the wild-type and mutant sequences expressed a full-length transcript and a short transcript lacking exon 9. Quantitation of the relative amount of the two transcripts indicated that the fraction of the full-length transcript derived from c.1275A>G is much lower than that derived from the wild-type (51.9% vs 77.4%). Extinction of two splicing factors (SF2/ASF and SC35) by RNA interference also affected c.1275A>G more seriously than the wild-type in terms of exon 9 skipping. Exon 9 skipping was presumed to cause a loss of GP2 function. This study represents the first detailed analysis of any variation in the GP2 gene and gives some support to the putative association of c.1275A>G with disease protection.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, U613, Brest, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Boulling
authors.forename: Gérald
authors.initials: G
authors.lastname: Le Gac
authors.forename: Gwendal
authors.initials: G
authors.lastname: Dujardin
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Chen
authors.forename: Claude
authors.initials: C
authors.lastname: Férec
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D019295:Computational Biology / Q000379:methods; D004742:Enhancer Elements, Genetic; D005091:Exons / Q000235:genetics*; D058851:GPI-Linked Proteins; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D050500:Pancreatitis, Chronic / Q000235:genetics*; D011110:Polymorphism, Genetic; D034622:RNA Interference; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: C489339:GP2 protein, human; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D012322:RNA Precursors; D012333:RNA, Messenger