Differential expression of neuroendocrine-specific protein in form-deprived chick eyes

PURPOSE. To identify genes that are highly expressed in form-deprived retin a-retinal pigment epithelium- choroid tissues. Neuroendocrine-specific prot eins were found to be highly expressed. METHODS. mRNAs enriched in retina-retinal pigment epithelium-choroid tissue s from 3-, 7-, and 14-day form-deprived chick eyes were isolated by differe ntial display technique with cDNA library screening. Neuroendocrine-specifi c protein A and C were cloned in control and form-deprived eyes. mRNA and p rotein levels, with respective regional localizations, were examined by Nor thern blot, Western blot, and immunohistochemical analyses, respectively. RESULTS. The isolated clone included an insert with a sequence homologous t o both chick neuroendocrine-specific proteins A and C. The increases in mRN A and protein level were confirmed by Northern and Western blot analyses, r espectively. Immunohistochemical localization of neuroendocrine-specific pr oteins A and C was detected in the layer of photoreceptor inner segments, p resumably in the cone cells. Northern blot analysis using negative lenses s howed that levels of neuroendocrine-specific protein A and C mRNAs were not altered using negative lenses. CONCLUSIONS. The expression of both neuroendocrine-specific proteins A and C mRNAs in cone photoreceptor cells was upregulated within 14 days of form deprivation, but not in response to negative spectacle lenses. These data s uggest that the increase in induction of neuroendocrine-specific proteins i s not a secondary consequence of ocular elongation or myopic refraction. In duction of neuroendocrine-specific proteins in form-deprived eyes may be ca usally related to the development of myopia or may be an unrelated effect o f form deprivation.