Conditional knockout system in cone photoreceptor cells

Abstract

Abstract: : Purpose: Disruption of fundamental genes in mice often leads to embryonic and neonatal lethality. To circumvent this problem and dissect gene functions in the cone photoreceptor cells, we decided to establish a cone photoreceptor–specific knockout system using the Cre/lox system. Methods: Transgenic mice expressing Cre recombinase directed by a promoter element of the human red/green pigment gene were generated. Mouse strains expressing Cre were identified with RT–PCR. Candidate Cre–expressing mice were further characterized with the imunocytochemical assays and functional studies using a Cre–activatable lacZ reporter mouse strain (ROSA26). Results: RT–PCR analysis suggested that several transgenic strains expressed Cre mRNA in the retina. ß–galactosidase assay on retinal flat mounts and sections of F1 mice derived from the Cre–expressing mice and the lacZ reporter mice suggested that at least one of these mouse strains was capable of carrying out productive Cre–mediated recombination in cone photoreceptor cells. Immunocytochemical staining with retinal sections from this mouse strain suggested that Cre expression is localized to cone photoreceptor cells in mice. Conclusion: We have generated transgenic mice that efficiently express Cre recombinase in cone photoreceptor cells. These mice can be potentially used in gene function studies in cone photoreceptor cells.

Keywords: photoreceptors • genetics • gene/expression