title: A sensitized mutagenesis screen identifies Gli3 as a modifier of Sox10 neurocristopathy.
abstract: Haploinsufficiency for the transcription factor SOX10 is associated with the pigmentary deficiencies of Waardenburg syndrome (WS) and is modeled in Sox10 haploinsufficient mice (Sox10(LacZ/+)). As genetic background affects WS severity in both humans and mice, we established an N-ethyl-N-nitrosourea (ENU) mutagenesis screen to identify modifiers that increase the phenotypic severity of Sox10(LacZ/+) mice. Analysis of 230 pedigrees identified three modifiers, named modifier of Sox10 neurocristopathies (Mos1, Mos2 and Mos3). Linkage analysis confirmed their locations on mouse chromosomes 13, 4 and 3, respectively, within regions distinct from previously identified WS loci. Positional candidate analysis of Mos1 identified a truncation mutation in a hedgehog(HH)-signaling mediator, GLI-Kruppel family member 3 (Gli3). Complementation tests using a second allele of Gli3 (Gli3(Xt-J)) confirmed that a null mutation of Gli3 causes the increased hypopigmentation in Sox10(LacZ/+);Gli3(Mos1/)(+) double heterozygotes. Early melanoblast markers (Mitf, Sox10, Dct, and Si) are reduced in Gli3(Mos1/)(Mos1) embryos, indicating that loss of GLI3 signaling disrupts melanoblast specification. In contrast, mice expressing only the GLI3 repressor have normal melanoblast specification, indicating that the full-length GLI3 activator is not required for specification of neural crest to the melanocyte lineage. This study demonstrates the feasibility of sensitized screens to identify disease modifier loci and implicates GLI3 and other HH signaling components as modifiers of human neurocristopathies.
authors.affiliation: Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Ivana
authors.initials: I
authors.lastname: Matera
authors.forename: Dawn E
authors.initials: DE
authors.lastname: Watkins-Chow
authors.forename: Stacie K
authors.initials: SK
authors.lastname: Loftus
authors.forename: Ling
authors.initials: L
authors.lastname: Hou
authors.forename: Arturo
authors.initials: A
authors.lastname: Incao
authors.forename: Debra L
authors.initials: DL
authors.lastname: Silver
authors.forename: Cecelia
authors.initials: C
authors.lastname: Rivas
authors.forename: Eugene C
authors.initials: EC
authors.lastname: Elliott
authors.forename: Laura L
authors.initials: LL
authors.lastname: Baxter
authors.forename: William J
authors.initials: WJ
authors.lastname: Pavan
mesh_terms: D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation; D002874:Chromosome Mapping; D018389:Codon, Nonsense; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000378:metabolism / Q000503:physiopathology; D005038:Ethylnitrosourea / Q000494:pharmacology; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D005816:Genetic Complementation Test; D006609:High Mobility Group Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008544:Melanocytes / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016296:Mutagenesis; D009153:Mutagens / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009432:Neural Crest / Q000187:drug effects / Q000196:embryology / Q000378:metabolism / Q000503:physiopathology*; D010858:Pigmentation; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D055757:SOXE Transcription Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014849:Waardenburg Syndrome / Q000196:embryology / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology*; D000074290:Zinc Finger Protein Gli3
chemical_list: D018389:Codon, Nonsense; D004268:DNA-Binding Proteins; C465571:Gli3 protein, mouse; D006609:High Mobility Group Proteins; D051741:Kruppel-Like Transcription Factors; D009153:Mutagens; D009419:Nerve Tissue Proteins; D012097:Repressor Proteins; C527923:SOX10 protein, human; D055757:SOXE Transcription Factors; C527924:Sox10 protein, mouse; D014157:Transcription Factors; D000074290:Zinc Finger Protein Gli3; D005038:Ethylnitrosourea