advertisement
Abstract #5569 Published in IGR 2-1
Lmx1b, a LIM homeodomain class transcription factor, is necessary for normal development of multiple tissues in the anterior segment of the murine eye
Pressman CL; Chen H; Johnson RLGenesis 2000; 26:15-25
Proper development of the anterior segment of the mammalian eye is critical for normal ocular function. Indeed, several congenital syndromes associated with anterior segment anomalies can lead to impaired vision and glaucoma. One such syndrome is nail patella syndrome (NPS), caused by haplo-insufficiency for the LIM-homeodomain transcription factor LMX1B. Although mutations in LMX1B cosegregate with NPS, whether these mutations cause the glaucoma associated with NPS is not known. Here, the authors provide evidence that the LIM-homeodomain transcription factor Imx1b is an essential regulator of murine anterior segment development. Mice that are homozygous for a targeted mutation of Imx1b display iris and ciliary body hypoplasia, and cornea stromal defects. In addition, two cDNAs normally downregulated in presumptive cornea, mf1 and mfh1, exhibit persistent expression, while keratocan, a keratin sulfate proteoglycan expressed by keratocytes, is not detected in mutant corneas. Moreover, ultrastructural examination of homozygous mutants indicates that corneal collagen fibrillogenesis is perturbed. Taken together, these studies suggest a developmental etiology for glaucoma in NPS patients and highlight Imx1b as an essential regulator of anterior segment morphogenesis and patterning.
Dr. R.L. Johnson, Department of Biochemistry and Molecular Biology, Program in Genes and Development, University of Texas, Houston, TX 77030, USA
Classification:
1.3 Pathogenesis (Part of: 1 General aspects)
