Faculty Collaboration Database

Deletion in the promoter region and altered expression of Pitx3 homeobox gene in aphakia mice. Hum Mol Genet 2000 Jul 01;9(11):1575-85

Date

06/22/2000

Pubmed ID

10861284

DOI

10.1093/hmg/9.11.1575

Scopus ID

2-s2.0-0034234546 (requires institutional sign-in at Scopus site)   162 Citations

Abstract

Mouse aphakia (ak) is a recessive phenotype that spontaneously occurs in the 129/Sv-SlJ strain and is characterized by small eyes that lack a lens. We have recently identified a homeobox-containing gene, Pitx3, and have shown that it is expressed in the developing lens and maps to chromosome 19 close to ak in mouse. Human PITX3 gene was found to underlie anterior segment dysgenesis and cataracts. We have now obtained the entire sequence of the mouse Pitx3 gene including 10 kb of the 5' region and 5 kb of the 3' region. Of several microsatellite repeat regions identified within the Pitx3 sequence, one was informative for linkage analysis. No recombination was observed between ak and the Pitx3 marker, indicating that these two loci are closely linked (0.2 +/- 0.2 cM). Additionally, Pitx3 transcripts were not detected in the ak/ak mice either in the lens placode or at later developmental stages of the lens by in situ hybridization. Since no differences were previously found between ak/ak and wild-type sequences in the Pitx3 coding region, we hypothesized that an etiologic mutation is located in the promoter or other regulatory regions. To test this hypothesis we studied the 5' flanking region of the Pitx3 gene. This analysis revealed a deletion of 652 bp located 2.5 kb upstream from the start point of the Pitx3 5' UTR sequence in ak/ak mice. The deletion co-segregated with the ak mutation and was not detected in 16 samples from 10 different mouse strains including the founder strains. Analysis of the 652 bp region identified sequences similar to consensus binding sites for transcription factors AP-2 and Maf that were shown to play a critical role in lens determination. These lines of evidence suggest that the abnormal ocular development in the aphakia mouse is due to the deletion upstream of the Pitx3 gene.

Author List

Semina EV, Murray JC, Reiter R, Hrstka RF, Graw J

Author

Elena V. Semina PhD Chief, Professor in the Ophthalmology and Visual Sciences department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Acetyltransferases
Animals
Aphakia
Base Sequence
DNA
Embryo, Mammalian
Female
Gene Expression Regulation, Developmental
Genes, Homeobox
Genetic Linkage
Guanine Nucleotide Exchange Factors
Homeodomain Proteins
In Situ Hybridization
Male
Membrane Proteins
Mice
Mice, Inbred AKR
Mice, Inbred C57BL
Mice, Inbred DBA
Mice, Inbred Strains
Mice, Mutant Strains
Molecular Sequence Data
Muridae
Nuclear Proteins
Paired Box Transcription Factors
Promoter Regions, Genetic
Sequence Analysis, DNA
Sequence Deletion
Transcription Factors