Evidence of Developmentaly Regulated Splicing of Cone Opsins

Abstract

Abstract: : Purpose: We have previously found that low expression of leukemia inhibitory factor (LIF) reduced maturation of rod and cone photoreceptors. In the course of studying the effects of LIF regulation of cone opsin expression we have cloned multiple alternatively spliced transcripts for M– and S–opsins. The goal of this study is to determine whether or not correct cone splicing is regulated during normal development and by gp130 activation. Methods: We have used RT–PCR, qRT–PCR , immuo–fluorescence, western blots and in situ hybridizations to determine efficiency of correct opsin splicing at different developmental ages, and in LIF transgenic mice. Results: RT–PCR data has shown that in the presence of LIF, expression of M– and S–opsin clones are smaller than normal and are missing internal exons which demonstrate alternative splicing. Our data also show that in normal development cone opsins are not spliced correctly at postnatal day 5, and that there is an induction of correct splicing before postnatal day 14. Conclusions: : Our expression analysis demonstrates that correct splicing of M–opsin (and perhaps S–opsin) is regulated in development and could possibly regulate cone outer segment synthesis and differentiation. Based on our results, we suspect that activating ligands of gp130 may be an important mechanism(s) to regulate cone opsin splicing and therefore regulate cone function.

Keywords: photoreceptors • retinal development • transgenics/knock-outs