A role for the deep orange and carnation eye color genes in lysosomal delivery in Drosophila

deep orange and carnation are two of the classic eye color genes in Drosoph ila, Here, we demonstrate that Deep orange is part of a protein complex tha t localizes to endosomal compartments. A second component of this complex i s Carnation, a homolog of Sec1p-like regulators of membrane fusion. Because complete loss of deep orange function is lethal, the role of this complex in intracellular trafficking was analyzed in deep orange mutant clones. Ret inal cells devoid of deep orange function completely lacked pigmentation an d exhibited exaggerated multivesicular structures, Furthermore, a defect in endocytic trafficking was visualized in developing photoreceptor cells. Th ese results provide direct evidence that eye color mutations of the granule group also disrupt vesicular trafficking to lysosomes.