title: Analysis of compound heterozygotes reveals that the mouse floxed Pax6 (tm1Ued) allele produces abnormal eye phenotypes.
abstract: Analysis of abnormal phenotypes produced by different types of mutations has been crucial for our understanding of gene function. Some floxed alleles that retain a neomycin-resistance selection cassette (neo cassette) are not equivalent to wild-type alleles and provide useful experimental resources. Pax6 is an important developmental gene and the aim of this study was to determine whether the floxed Pax6 (tm1Ued) (Pax6 (fl) ) allele, which has a retained neo cassette, produced any abnormal eye phenotypes that would imply that it differs from the wild-type allele. Homozygous Pax6 (fl/fl) and heterozygous Pax6 (fl/+) mice had no overt qualitative eye abnormalities but morphometric analysis showed that Pax6 (fl/fl) corneas tended be thicker and smaller in diameter. To aid identification of weak effects, we produced compound heterozygotes with the Pax6 (Sey-Neu) (Pax6 (-)) null allele. Pax6 (fl/-) compound heterozygotes had more severe eye abnormalities than Pax6 (+/-) heterozygotes, implying that Pax6 (fl) differs from the wild-type Pax6 (+) allele. Immunohistochemistry showed that the Pax6 (fl/-) corneal epithelium was positive for keratin 19 and negative for keratin 12, indicating that it was abnormally differentiated. This Pax6 (fl) allele provides a useful addition to the existing Pax6 allelic series and this study demonstrates the utility of using compound heterozygotes with null alleles to unmask cryptic effects of floxed alleles.
authors.affiliation: Genes and Development Group, Centre for Integrative Physiology, Biomedical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
authors.forename: Natalie J
authors.initials: NJ
authors.lastname: Dorà
authors.affiliation: Genes and Development Group, Centre for Integrative Physiology, Biomedical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
authors.forename: Aaron J F
authors.initials: AJ
authors.lastname: Crookshanks
authors.affiliation: Genes and Development Group, Centre for Integrative Physiology, Biomedical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
authors.forename: Karen K Y
authors.initials: KK
authors.lastname: Leung
authors.affiliation: Genes and Development Group, Centre for Integrative Physiology, Biomedical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.|Institute for Adaptive and Neural Computation, School of Informatics, University of Edinburgh, 10 Crichton Street, Edinburgh, EH8 9AB, UK.|Biomathematics and Statistics Scotland, James Clerk Maxwell Building, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK.
authors.forename: T Ian
authors.initials: TI
authors.lastname: Simpson
authors.affiliation: Genes and Development Group, Centre for Integrative Physiology, Biomedical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
authors.forename: John O
authors.initials: JO
authors.lastname: Mason
authors.affiliation: Genes and Development Group, Centre for Integrative Physiology, Biomedical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Price
authors.affiliation: Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK. John.West@ed.ac.uk.
authors.forename: John D
authors.initials: JD
authors.lastname: West
mesh_terms: D000483:Alleles; D000818:Animals; D019573:Epithelium, Corneal / Q000378:metabolism / Q000503:physiopathology*; D005123:Eye / Q000378:metabolism / Q000503:physiopathology*; D005124:Eye Abnormalities / Q000235:genetics* / Q000503:physiopathology; D005838:Genotype; D006579:Heterozygote; D006720:Homozygote; D051379:Mice; D018345:Mice, Knockout; D000071841:PAX6 Transcription Factor / Q000235:genetics*; D010641:Phenotype
chemical_list: D000071841:PAX6 Transcription Factor; C000605732:Pax6 protein, mouse
keywords: Corneal epithelium; Eye; Floxed allele; Keratin 12; Pax6