Defective pigment granule biogenesis and aberrant behavior caused by mutations in the Drosophila AP-3beta adaptin gene ruby.
Lysosomal protein trafficking is a fundamental process conserved from yeast to humans. This conservation extends to lysosome-like organelles such as mammalian melanosomes and insect eye pigment granules. Recently, eye and coat color mutations in mouse (mocha and pearl) and Drosophila (garnet and carmine) were shown to affect subunits of the heterotetrameric adaptor protein complex AP-3 involved in vesicle trafficking. Here we demonstrate that the Drosophila eye color mutant ruby is defective in the AP-3beta subunit gene. ruby expression was found in retinal pigment and photoreceptor cells and in the developing central nervous system. ruby mutations lead to a decreased number and altered size of pigment granules in various cell types in and adjacent to the retina. Humans with lesions in the related AP-3betaA gene suffer from Hermansky-Pudlak syndrome, which is caused by defects in a number of lysosome-related organelles. Hermansky-Pudlak patients have a reduced skin pigmentation and suffer from internal bleeding, pulmonary fibrosis, and visual system malfunction. The Drosophila AP-3beta adaptin also appears to be involved in processes other than eye pigment granule biogenesis because all ruby allele combinations tested exhibited defective behavior in a visual fixation paradigm.
Kretzschmar
D
D
Lehrstuhl für Genetik, Theodor-Boveri-Institut, Biozentrum, Universität Würzburg, D 97074 Würzburg, Germany.
Poeck
B
B
Roth
H
H
Ernst
R
R
Keller
A
A
Porsch
M
M
Strauss
R
R
Pflugfelder
G O
GO
D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D000818:Animals; D001522:Behavior, Animal; D002490:Central Nervous System / Q000196:embryology; D004330:Drosophila / Q000196:embryology / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins; D006801:Humans; D019476:Insect Proteins / Q000235:genetics / Q000502:physiology*; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D034041:Monomeric Clathrin Assembly Proteins; D016296:Mutagenesis; D009154:Mutation; D012160:Retina / Q000196:embryology*; D012168:Retinal Pigments; D017386:Sequence Homology, Amino Acid
D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; D029721:Drosophila Proteins; D019476:Insect Proteins; D008565:Membrane Proteins; D034041:Monomeric Clathrin Assembly Proteins; C410303:RB protein, Drosophila; D012168:Retinal Pigments; C439023:clathrin assembly protein AP180