title: A SNP in the Immunoregulatory Molecule CTLA-4 Controls mRNA Splicing In Vivo but Does Not Alter Diabetes Susceptibility in the NOD Mouse.
abstract: CTLA-4 is a critical "checkpoint" regulator in autoimmunity. Variation in CTLA-4 isoform expression has been linked to type 1 diabetes development in human and NOD mouse studies. In the NOD mouse, a causative link between increased expression of the minor isoform ligand-independent CTLA-4 and a reduction in diabetes has become widely accepted. Altered splicing of CTLA-4 has been attributed to a single nucleotide polymorphism (SNP) in Ctla4 exon2 (e2_77A/G). To investigate this link, we have used NOD embryonic stem (ES) cells to generate a novel NOD transgenic line with the 77A/G SNP. This strain phenocopies the increase in splicing toward the liCTLA4 isoform seen in B10 Idd5.1 mice. Crucially, the SNP does not alter the spontaneous incidence of diabetes, the incidence of cyclophosphamide-induced diabetes, or the activation of diabetogenic T-cell receptor transgenic CD4(+) T cells after adoptive transfer. Our results show that one or more of the many other linked genetic variants between the B10 and NOD genome are required for the diabetes protection conferred by Idd5.1. With the NOD mouse model closely mimicking the human disease, our data demonstrate that knock-in transgenic mice on the NOD background can test causative mutations relevant in human diabetes.
authors.affiliation: Department of Pathology, University of Cambridge, Cambridge, U.K.
authors.forename: Fabian
authors.initials: F
authors.lastname: Jakubczik
authors.affiliation: Wellcome Trust Centre for Stem Cell Research, University of Cambridge, Cambridge, U.K. Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, U.K.
authors.forename: Ken
authors.initials: K
authors.lastname: Jones
authors.affiliation: Wellcome Trust Centre for Stem Cell Research, University of Cambridge, Cambridge, U.K. Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, U.K.
authors.forename: Jennifer
authors.identifier: 0000-0002-8650-1388
authors.initials: J
authors.lastname: Nichols
authors.affiliation: Wellcome Trust Centre for Stem Cell Research, University of Cambridge, Cambridge, U.K.
authors.forename: William
authors.initials: W
authors.lastname: Mansfield
authors.affiliation: Department of Pathology, University of Cambridge, Cambridge, U.K.
authors.forename: Anne
authors.identifier: 0000-0003-3327-6081
authors.initials: A
authors.lastname: Cooke
authors.affiliation: Department of Pathology, University of Cambridge, Cambridge, U.K. nh106@cam.ac.uk.
authors.forename: Nick
authors.initials: N
authors.lastname: Holmes
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D015551:Autoimmunity / Q000235:genetics* / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D060908:CTLA-4 Antigen / Q000235:genetics* / Q000276:immunology; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics* / Q000276:immunology; D055879:Gene Knock-In Techniques; D020022:Genetic Predisposition to Disease; D051379:Mice; D016688:Mice, Inbred NOD; D008822:Mice, Transgenic; D000066450:Mouse Embryonic Stem Cells; D020641:Polymorphism, Single Nucleotide; D020033:Protein Isoforms; D012326:RNA Splicing / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*
chemical_list: D060908:CTLA-4 Antigen; C556707:Ctla4 protein, mouse; D020033:Protein Isoforms; D012333:RNA, Messenger