title: Differences in corneal phenotypes between destrin mutants are due to allelic difference and modified by genetic background.
abstract: OBJECTIVE
  Mutations in destrin (Dstn) cause corneal abnormalities in mice. A null mutation, Dstn(corn1), results in corneal epithelial hyperproliferation, inflammation, and neovascularization in the A.BY background (A.BY Dstn(corn1)). Homozygosity for a point mutation, Dstn(corn1-2J), results in mild thickening of the corneal epithelium but no corneal neovascularization in a C57BL/6 (B6) background (B6 Dstn(corn1-2J)). The goal of this study was to determine whether phenotypic differences are due to allelic differences between Dstn(corn1) and Dstn(corn1-2J), or are the result of genetic background effects.
  
  
  METHODS
  We generated two congenic (Cg) mouse lines, B6.Cg-Dstn(corn1) and A.BY.Cg-Dstn(corn1-2J), to compare to the original A.BY Dstn(corn1) and B6 Dstn(corn1-2J) lines. We performed immunohistochemistry to assay F-actin accumulation, neovascularization, proliferation, and inflammation. By western blot analysis we tested the expression of serum response factor (SRF), a known regulator of the Dstn(corn1) phenotype.
  
  
  RESULTS
  The Dstn(corn1) mutation leads to neovascularization, hyperproliferation, and inflammation in the cornea of A.BY Dstn(corn1) as well as B6.Cg-Dstn(corn1) mice. We did not observe significant corneal neovascularization or hyperproliferation in either A.BY.Cg-Dstn(corn1-2J) or B6 Dstn(corn1-2J) mice. Actin accumulation, neovascularization, epithelial proliferation and inflammation in B6.Cg-Dstn(corn1) cornea are significantly reduced when compared to A.BY Dstn(corn1)cornea. SRF changes are consistent in Dstn(corn1) mutants, regardless of genetic background.
  
  
  CONCLUSIONS
  Differences in the abnormal phenotypes of Dstn mutants result from allelic differences between Dstn(corn1) and Dstn(corn1-2J) . Moreover, phenotypes of Dstn(corn1) mice are modified by genetic background, suggesting the existence of genetic modifiers. Protein analysis suggests that a genetic modifier affects phenotypic severity functionally downstream from or in a pathway independent from SRF. These data demonstrate that natural genetic variation affects phenotypic severity in Dstn(corn1) mice.
authors.affiliation: Department of Medical Genetics, University of Wisconsin, Madison, WI 53705, USA.
authors.forename: Sharolyn V
authors.initials: SV
authors.lastname: Kawakami-Schulz
authors.forename: Angela M
authors.initials: AM
authors.lastname: Verdoni
authors.forename: Shannon G
authors.initials: SG
authors.lastname: Sattler
authors.forename: Akihiro
authors.initials: A
authors.lastname: Ikeda
authors.forename: Sakae
authors.initials: S
authors.lastname: Ikeda
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000483:Alleles; D000818:Animals; D003315:Cornea / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology; D016510:Corneal Neovascularization / Q000235:genetics* / Q000378:metabolism; D051345:Destrin / Q000235:genetics* / Q000378:metabolism; D018703:Founder Effect; D015870:Gene Expression; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation; D010641:Phenotype; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D012720:Severity of Illness Index
chemical_list: D000199:Actins; D051345:Destrin; C495825:Dstn protein, mouse; D011494:Protein Kinases; C405628:serum response factor kinase