Mouse opsin promoter-directed Cre recombinase expression intransgenic mice

[摘要] Purpose: Gene inactivation with homologous recombination in mice isa widely used tool to study gene function. However, many proteins playessential roles in a number of tissues and germline gene inactivationoften results in embryonic lethality. To overcome this limitation and todissect the functions of essential genes beyond embryonic development,we generated mouse rod opsin promoter-controlled cre transgenic micewith a goal of obtaining transgenic lines with a range of Cre activityin rod photoreceptors.Methods: Transgenic mice expressing Cre recombinase directed by along or short mouse opsin promoter were generated. CandidateCre-expressing lines were identified with RT-PCR and Western blotanalysis. Potentially useful Cre-expressing lines were characterizedfurther with immunohistochemistry, PCR, and functional analysis using aCre-activatable lacZ reporter mouse strain (R26R) to determinetemporal and spatial patterns of Cre expression. Retinal function andmorphology in these mouse lines were analyzed with electroretinography(ERG) and light microscopy of hematoxylin and eosin stained retinalsections.Results: Transgenic mice expressing Cre in rod photoreceptors weregenerated. Characterization of candidate photoreceptor-specific Cre miceusing immunohistochemistry and functional assays demonstrated that anefficient Cre-mediated recombination occurred in rod photoreceptor cellsin one mouse line and a mosaic Cre-mediated recombination occurred inrod photoreceptors and rod bipolar cells in another mouse line. Furtheranalysis of these mice with ERG and morphological examination suggestedthat the retinas of eight-month-old adults were normal.Conclusions: We have generated transgenic mice expressing Crerecombinase in rod photoreceptors. One transgenic mouse line was capableof carrying out efficient Cre-mediated recombination in rodphotoreceptors. Another transgenic mouse line was capable of carryingout mosaic Cre-mediated recombination in rod photoreceptors and bipolarcells across the whole retina. These mice will be useful tools forCre/lox-based gene activation and inactivation, as well as geneticmosaics, in rod photoreceptors and rod bipolar cells.

[学科分类] 生物化学/生物物理