Dystrophin isoforms expressed in the mouse retina

The dystrophin gene is expressed in various tissues of the mouse. Previous immunohistochemical studies suggested the existence of dystrophin protein in the outer plexiform layer of the retina. We analyzed mRNAs from the retina and other tissues of mice and detected the dystrophin transcripts (DT) with the use of the reverse transcription and polymerase chain reaction (RT-PCR) method. The 5′ sequences, corresponding to the first exon, of DT in the retina was mainly the brain type, whereas in the 3′ region of DT that corresponds to the C-terminal domain of dystrophin, some additional RT-PCR products were detected. Base sequences in three of them showed homology to those for previously reported human dystrophin isoforms. The DT variations in mice were identical between the retina and the brain. It was thus concluded that dystrophin really expresses in the mouse retina and most of the retinal dystrophin proteins belong to the brain type isoform.