Purpose: Viriligo (miut/miut) mice have i slow progressive loss of photoreceptor cells and abnormalities within the RPE including uneven pigmentation, reduced outer segment disk phagocytosis and abnormal microvillous processes. The genetic defect in this mutant is a point mutation in the microphthalmia (mi) gene, which codes for a basichelix-loop-helix zipper protein, a putative regulator of the transcription of some pigmentation genes. The purpose of this study was to assess the onset and spatial pattern of expression of m mRNA in vitiligo mutants. Methods: Mutant and wildrype embryos at various stages of d<velopment were subjected to wholemount in situ hybridization using a digoxigenin- labeled antisense RNA probe against mi. Following analysis of the wholemounts, labeled embryos were paraffin embedded, sectioned at 20ujn and examined by ligh- microscopy to determine the precise cellular location of expression. Results: Analysis revealed the expression of mi in eyes of wildtype and vitiligo mice as early as E1(. Gross inspection suggested that at this age expression was uniform in both mutants md controls. There was also mi expression in a migratory cell population in the postotic region at E10.5 through E11.5. Light microscopic examination of the histolojjc sections indicated that m expression was specific to the RPE. Conclusions; The data represent the first analysis of the mi gene in the vitiligo mutant mouse. The res alts demonstrate that the gene is expressed specifically in the RPE and at a stage preceding the normal onset of RPE pigmentation.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - Dec 1 1997|
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience