Localization of TIMP-3 mRNA expression to the retinal pigment epithelium

Purpose. To evaluate ocular sites of expression of the tissue inhibitor of metalloproteinase-3 gene (TIMP-3). Methods. In situ hybridization was performed on frozen sections of albino mouse eyes using riboprobes generated to the 3' untranslated region of TIMP-3. Results. TIMP-3 mRNA expression was detected strongly in the retinal pigment epithelium (RPE) and to a minor extent in the ciliary epithelium, but not at any other site within the eye. Conclusions. Expression of TIMP-3 in the RPE is consistent with the recent demonstration of TIMP-3 mutations in patients with Sorsby's fundus dystrophy, a condition marked by the early onset of choroidal neovascularization in the macula. Unlike many of the recently described genes that cause human retinal disease, TIMP-3 is preferentially expressed in the RPE of the normal eye, as opposed to the photoreceptors.