Abstract
Abstract: :
Purpose: The use of cre and other recombinases for conditional gene targeting allows removal of genes in a tissue specific manner. Many genes implicated in ocular disease have been studied using traditional transgenic and knock-out strategies. However, some genes important in disease pathophysiology are critical for the normal development and homeostasis, and thus cannot be studied by these techniques. Conditional gene expression in the eye using cre-recombinase is one technique that will allow genes to be turned on or off in a specfic subset of cells. We have produced transgenic mice that express cre-recombinase in the retina. Methods:The gene encoding cre-recombinase with an N-terminal nuclear localization sequence was placed behind the 4.2kb P0 element of the PAX-6 promoter. Five independent lines of cre transgenic mice were generated and crossed to the ROSA26 line of floxed betagalactosidase reporter mice. Retinas from doubly transgenic progeny and control littermates were evaluated by X-gal histochemistry in adult and neonatal mice in whole-mount preparation and in plastic sections. Results:Four of the five P0 cre transgenic mouse lines express cre-recombinase in the retina. Each of these four lines leads to cre expression in different cell types and spatial domains of the retina. One of the transgenic lines demonstrates strong cre expression in the peripheral retina in retinal ganglion cells, amacrine cells, and photoreceptors. Another line expresses cre recombinase only in retinal ganglion cells and amacrine cells throughout the retina. A third line expresses cre recombinase in the posterior pole in retinal ganglion cells, amacrine cells, and photoreceptors. Conclusion:The P0 element of the PAX-6 promoter is sufficient to drive retinal cre expression and activate transcription of functional betagalactosidase in the retina. Crosses between these cre-transgenic mice and mice with conditionally targeted genes will allow us to investigate the role of these genes in retinal development and function. Supported in part by grants from NEI (EY12910), Research to Prevent Blindness, the R. Silbermann Foundation, the Mackall Foundation Trust, and the Abramson Cancer Center.
Keywords: 554 retina • 606 transgenics/knock-outs • 417 gene/expression