Identification of additional outer segment targeting signals in zebrafish rod opsin

ABSTRACT In vertebrate photoreceptors, opsins are highly concentrated in a morphologically distinct ciliary compartment known as the outer segment (OS). Opsin is synthesized cell body and transported to OS at remarkable rate of 100 1000 molecules per second. transport defects contribute photoreceptor loss blindness human ciliopathies. Previous studies revealed that rhodopsin C-terminal tail, 44 amino acids, sufficient mediate targeting Xenopus photoreceptors. Here, we show that, although C-terminus retains this function zebrafish, homologous zebrafish sequence not target opsin OS. This functional difference largely caused by change single acid present but other vertebrates examined. Furthermore, find sequences third intracellular cytoplasmic loop (IC3) adjacent regions transmembrane helices 6 7 also necessary for zebrafish. Combined with these compartment.