Musashi 1 promotes the inclusion of photoreceptor specific exons.

<p><b>(A)</b> RT-PCR analysis of the inclusion levels of 11 exons with elevated inclusion levels in photoreceptors in N2A cell transfected with Flag-tagged MSI1 expression construct. The exon included and exon skipped isoforms are indicated with ‘+’ and ‘-’ respectively. On the right, western blot shows the expression of the flag-tagged Msi1 protein. <b>(B)</b> Chart showing the quantification of the inclusion levels of seven exons affected by the Msi1 protein. <b>(C)</b> Diagram showing a protein interaction network enriched in photoreceptor specific isoforms. The network is centered on Cep290 and the BBsome. Genes containing “switch-like” exons are shown in dark red or green. Red and green colors indicate inclusion and skipping in photoreceptors, respectively. Genes containing exons differentially spliced in photoreceptors are shown in pale red or green.