Reduced expression of vps11 causes less pigmentation in medaka, Oryzias latipes

In this article, we describe the medaka mutant pale gray eyes (pge) that shows reduction of black, white, and silver pigmentation and lethality approximately a week after hatching. The pge mutation was mapped to the tip of linkage group 14 and no recombinations were observed between the mutation and medaka vps11 in 900 meioses. Vps 11 is one of the evolutionarily conserved class C vacuolar protein sorting genes (c-vps: vps11, vps16, vps18, and vps33), whose products physically associate to form the c-vps protein complex required for vesicle docking and fusion in the budding yeast. Mutations in vps16, vps18, and vps33 are known to result in decreased pigmentation in organisms such as Drosophila. We cloned the full-length medaka vps11 cDNA by rapid amplification of cDNA ends (RACE) and found no RACE products from the pge mutants. Similarly, no vps11 transcripts were detected from the pge mutants by Northern analysis. The injection of an antisense morpholino against vps11 phenocopied the pge mutant. Taken together, the results suggest that reduced expression of medaka vps11 causes pge and that medaka vps11 is indispensable for survival and normal pigmentation.