Systematic immunolocalization of retinoid receptors in developing and adult mouse eyes

PURPOSE. TO determine the localization of retinoic acid receptors (RAR) alp ha, beta, and gamma and retinoid X receptors (RXR) alpha, beta, and gamma i n developing and adult mouse eyes at the level of single cells. METHODS. Immunohistochemistry was performed on paraformaldehyde-lysine-peri odate-fixed cryosections of mouse eyes, from embryonic day 10.5 to adulthoo d, with polyclonal antibodies directed against each receptor isoform. Histo logic sections from null mutant mice for each receptor served as negative c ontrols. RESULTS. RAR alpha was present ubiquitously in the prenatal eye and prefere ntially located in the posnatal retina and ciliary body. RAR beta was detec ted predominantly in the periocular mesenchyme and ciliary body. RAR gamma was distributed in the periocular mesenchyme, choroid, sclera, cornea, conj unctiva, and lids. RXR alpha was found preferentially in the prenatal perio cular mesenchyme and retina and in the postnatal ciliary body, cornea, and conjunctiva. RXR beta was ubiquitous at all the stages. RXR gamma was detec ted mainly in subsets of prenatal retinal cells and in postnatal ganglion c ells as well, as a subset of photoreceptor cells that were characterized as cones in adults. CONCLUSIONS. RAR alpha, beta, and gamma and RXRa and y exhibit specific and dynamic patterns of distribution in ocular tissues throughout the course o f development. The abundance of RAR beta, RAR gamma, and RXR alpha in the p eriocular mesenchyme suggests that this tissue represents an important site of retinoid actions during eye development and in adulthood.