Abstract
Abstract: :
Purpose: NRL, a rod-specific transcription factor, is required for the expression of rod specific genes in mice. Null mutation of NRL results in a complete absence of rod photoreceptor cells. The goals of this study are (1) to identify the critical promoter region for rod specific expression and (2) generate transgenic mice expressing GFP under the control of the mouse Nrl promoter as a tool to understand photoreceptor cell development. Methods: Transgenic mice were generated by injecting one-cell stage mouse embryos with plasmid vector pEGFP1 (Clontech) containing three different lengths (l, m, and s) of the mouse Nrl upstream promoter, and the EGFP reporter gene. Insertion of the transgene was detected by PCR and Southern blotting. Retinal specific expression was examined by Western blotting and fluorescent microscopy. In vitro studies of the Nrl promoter was also done by transfection to Y79 cells. Results: Nrl-l-EGFP transgenic mice show photoreceptor-specific expression of GFP by Western blotting and fluorescence microscopy, but Nrl-m-EGFP and Nrl-s-EGFP transgenic mice do not express GFP. Conclusion: This study suggests that a rod specific enhancer region is present in the upstream region of Nrl promoter. Based on Nrl's function, we propose that cells expressing GFP in E18.5 to P0.5 mouse retina are rod precursor cells which will be valuable for investigating rod differentiation.
Keywords: 606 transgenics/knock-outs • 517 photoreceptors • 604 transcription