Expression of Pax-6 mRNA in the retinal degeneration (rd) mouse.

The homeobox gene Pax-6 is expressed during eye development in both the retina and lens, and Pax-6 mutations cause ocular abnormalities including retinal defects. We investigated the pattern of Pax-6 gene expression in the rd/rd mouse model of inherited retinal degeneration in comparison with nondegenerative controls, using Northern blot, reverse-transcription (RT)-PCR and in situ hybridization analysis. We observed an increased level of Pax-6 mRNA expression in the degenerative state, which appeared to affect equally the major Pax-6 exon 5a transcriptional splice variants as detected by RT-PCR. By in situ hybridization, Pax-6 mRNA was localized to the inner nuclear and ganglion cell layers of nondegenerative retina, but showed a more diffuse signal pattern in the rd/rd retina. This modulation of Pax-6 mRNA levels and localization is suggestive of activation of expression in retinal glial cells and may reflect reorganization of cellular interactions in response to the degenerative processes. Copyright 1998 Academic Press.