Limits...
Differences in corneal phenotypes between destrin mutants are due to allelic difference and modified by genetic background.

Kawakami-Schulz SV, Verdoni AM, Sattler SG, Ikeda A, Ikeda S - Mol. Vis. (2012)

Bottom Line: 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.Actin accumulation, neovascularization, epithelial proliferation and inflammation in B6.Cg-Dstn(corn1) cornea are significantly reduced when compared to A.BY Dstn(corn1)cornea.Differences in the abnormal phenotypes of Dstn mutants result from allelic differences between Dstn(corn1) and Dstn(corn1-2J) .

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Genetics, University of Wisconsin, Madison, WI 53705, USA.

ABSTRACT

Purpose: Mutations in destrin (Dstn) cause corneal abnormalities in mice. A 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.

Show MeSH

Related in: MedlinePlus

Neovascularization phenotype in F1 Dstncorn1 progeny. A: Immunofluorescence for CD31 highlights blood vessels that infiltrate A.BY Dstncorn1, B6.Cg-Dstncorn1, and F1 (A.BY Dstncorn1 x B6.Cg-Dstncorn1) cornea. Bar, 200 μm. B: The amount of neovascularization in F1 Dstncorn1 mice is intermediate to and significantly different from either parental strain. Sample sizes: A.BY Dstncorn1 P58 n=11, F1 Dstncorn1 P58 n=14, B6.Cg-Dstncorn1 n=10. Error bars, SEM * denotes statistical significance resulting from t-tests. *p<0.05, **p<0.01, ***p<0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3298451&req=5

f7: Neovascularization phenotype in F1 Dstncorn1 progeny. A: Immunofluorescence for CD31 highlights blood vessels that infiltrate A.BY Dstncorn1, B6.Cg-Dstncorn1, and F1 (A.BY Dstncorn1 x B6.Cg-Dstncorn1) cornea. Bar, 200 μm. B: The amount of neovascularization in F1 Dstncorn1 mice is intermediate to and significantly different from either parental strain. Sample sizes: A.BY Dstncorn1 P58 n=11, F1 Dstncorn1 P58 n=14, B6.Cg-Dstncorn1 n=10. Error bars, SEM * denotes statistical significance resulting from t-tests. *p<0.05, **p<0.01, ***p<0.001.

Mentions: Our results suggest that phenotypic differences between Dstn mutants are due to allelic differences. Actin accumulation, neovascularization, proliferation and inflammatory response differences between Dstncorn1 and Dstncorn1–2J remain consistent when compared in two genetic backgrounds. Notably, phenotypes caused by the Dstncorn1mutation are also modified by genetic background. In every case, the abnormal phenotype is dampened in the cornea of B6.Cg-Dstncorn1 mice compared to A.BY Dstncorn1 mice. We crossed the Dstncorn1 mutants and found that F1 mice demonstrate a level of neovascularization that is intermediate to and significantly different from A.BY Dstncorn1 and B6.Cg-Dstncorn1 (Figure 7A,B). These results suggest the presence of a genetic factor that is variable between B6 and A.BY and affects the phenotype in a dosage-dependent manner.


Differences in corneal phenotypes between destrin mutants are due to allelic difference and modified by genetic background.

Kawakami-Schulz SV, Verdoni AM, Sattler SG, Ikeda A, Ikeda S - Mol. Vis. (2012)

Neovascularization phenotype in F1 Dstncorn1 progeny. A: Immunofluorescence for CD31 highlights blood vessels that infiltrate A.BY Dstncorn1, B6.Cg-Dstncorn1, and F1 (A.BY Dstncorn1 x B6.Cg-Dstncorn1) cornea. Bar, 200 μm. B: The amount of neovascularization in F1 Dstncorn1 mice is intermediate to and significantly different from either parental strain. Sample sizes: A.BY Dstncorn1 P58 n=11, F1 Dstncorn1 P58 n=14, B6.Cg-Dstncorn1 n=10. Error bars, SEM * denotes statistical significance resulting from t-tests. *p<0.05, **p<0.01, ***p<0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3298451&req=5

f7: Neovascularization phenotype in F1 Dstncorn1 progeny. A: Immunofluorescence for CD31 highlights blood vessels that infiltrate A.BY Dstncorn1, B6.Cg-Dstncorn1, and F1 (A.BY Dstncorn1 x B6.Cg-Dstncorn1) cornea. Bar, 200 μm. B: The amount of neovascularization in F1 Dstncorn1 mice is intermediate to and significantly different from either parental strain. Sample sizes: A.BY Dstncorn1 P58 n=11, F1 Dstncorn1 P58 n=14, B6.Cg-Dstncorn1 n=10. Error bars, SEM * denotes statistical significance resulting from t-tests. *p<0.05, **p<0.01, ***p<0.001.
Mentions: Our results suggest that phenotypic differences between Dstn mutants are due to allelic differences. Actin accumulation, neovascularization, proliferation and inflammatory response differences between Dstncorn1 and Dstncorn1–2J remain consistent when compared in two genetic backgrounds. Notably, phenotypes caused by the Dstncorn1mutation are also modified by genetic background. In every case, the abnormal phenotype is dampened in the cornea of B6.Cg-Dstncorn1 mice compared to A.BY Dstncorn1 mice. We crossed the Dstncorn1 mutants and found that F1 mice demonstrate a level of neovascularization that is intermediate to and significantly different from A.BY Dstncorn1 and B6.Cg-Dstncorn1 (Figure 7A,B). These results suggest the presence of a genetic factor that is variable between B6 and A.BY and affects the phenotype in a dosage-dependent manner.

Bottom Line: 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.Actin accumulation, neovascularization, epithelial proliferation and inflammation in B6.Cg-Dstn(corn1) cornea are significantly reduced when compared to A.BY Dstn(corn1)cornea.Differences in the abnormal phenotypes of Dstn mutants result from allelic differences between Dstn(corn1) and Dstn(corn1-2J) .

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Genetics, University of Wisconsin, Madison, WI 53705, USA.

ABSTRACT

Purpose: Mutations in destrin (Dstn) cause corneal abnormalities in mice. A 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.

Show MeSH
Related in: MedlinePlus