Abstract
Abstract: :
Purpose: To determine the genes in the early developing eye that are regulated by Chx10. Chx10 encodes a homeodomain transcription factor that is initially expressed in dividing retinal neuroepithelial cells, but then down-regulated as differentiation proceeds. At later developmental stages, it is strongly and selectively expressed in bipolar cells. We recently showed that the recessive murine mutation ocular retardation (orJ) results from a null allele of Chx10 (Burmeister et al., 1996). The eye-specific phenotype is manifest in three fundamental aspects of retinal development. First, proliferation of retinal neuroepithelial cells is reduced from the early stages of retinal morphogenesis, resulting in microphthalmia. Second, intraretinal guidance of retinal ganglion cell (RGC) axons is profoundly disrupted, leading to optic nerve aplasia. And third, bipolar cells fail to differentiate, in effect creating a selective "knock-out" of this cell type. In order to understand the changes in eye development resulting from the Chx10 null, we are using I-gene arrays to develop an expression profile of the developing orJ eye. Methods: I-gene arrays, containing ≷6500 eye genes/ESTs printed in duplicate onto glass slides, were hybridized to Cy3 or Cy5 labeled target RNA from embryonic day 15.5 wild-type (+/+) and orJ/orJ eyes. Images are analyzed with GLEAMS software (Nutec). Data analysis is in progress and will be performed using data-driven normalization methods. Real-time PCR is being used to confirm the changes in gene expression. Results: On-going analysis of I-gene arrays has defined a set of genes that are differentially expressed in the orJ/orJ eye. Some of these changes are being confirmed with real-time RT-PCR. A number of genes are currently uncharacterized. A comprehensive analysis of the data will be presented. Conclusion: This data represents an initial effort to discover the molecular pathways regulated by Chx10.