The myocilin (MYOC) gene expression in the human trabecular meshwork

Purpose. We previously reported a novel cytoskeletal protein with a myosin- like domain which is localized in the ciliary rootlet and basal body of con necting cilium of photoreceptor and hence we named it 'myocilin'. It was so on realized that myocilin is identical to a protein called TIGR (trabecular meshwork inducible glucocorticoid response protein) which was found to be responsible for the pathogenesis of juvenile open angle glaucoma. In this s tudy, we employed in situ RNA hybridization to examine the myocilin (MYOC)/ TIGR gene expression in the trabecular meshworks of glaucomatous and nongla ucomatous eyes. Methods. The glaucomatous specimens were obtained by trabeculectomy from th e patients with primary open angle glaucoma (POAG), chronic angle closure g laucoma (CACG) and steroid glaucoma, respectively, and the nonglaucomatous specimens were obtained from a victim of traffic accident at autopsy and fr om a patient with maxillary sinus carcinoma at enucleation for the operatio n. The in situ RNA hybridization was carried out with digoxigenin-labeled s ense and antisense RNA probes. Results. In all cases, hybridization signals were detected primarily in the trabecular meshwork cells and secondarily in the fibroblast-like cells of corneoscleral wall. Conclusions. Myocilin gene is expressed clearly in the trabecular meshwork cells of both glaucomatous and nonglaucomatous eyes.