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Membrane domain modulation by Spectrins in Drosophila photoreceptor morphogenesis
Author(s) -
Chen Tony W.,
Chen Geng,
Funkhouser Lisa J.,
Nam SangChul
Publication year - 2009
Publication title -
genesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.093
H-Index - 110
eISSN - 1526-968X
pISSN - 1526-954X
DOI - 10.1002/dvg.20555
Subject(s) - spectrin , morphogenesis , biology , microbiology and biotechnology , cytoskeleton , gene , biochemistry , cell
Spectrins are major proteins in the cytoskeletal network of most cells. In Drosophila , β Heavy ‐Spectrin encoded by the karst gene functions together with Crb during photoreceptor morphogenesis. However, the roles of two other Spectrins (α‐ and β‐ Spectrins ) in developing photoreceptor cells have not been studied. Here, we analyzed the effects of spectrin mutations on developing eyes to determine their roles in photoreceptor morphogenesis. We found that the Spectrins are dispensable for retinal differentiation in eye imaginal discs during larval stage. However, photoreceptors deficient in α‐ or β‐Spectrin display dramatic apical membrane expansions including Crb and show morphogenesis defects during pupal eye development, suggesting that α‐ and β‐Spectrins are specifically required for photoreceptor polarity during pupal eye development. Karst localizes apically, whereas β‐Spectrin is preferentially distributed in the basolateral region. We show that overexpression of β‐Spectrin causes a strong shrinkage of apical membrane domains, and loss of β‐Spectrin causes an expansion of apical domains, implying an antagonistic relationship between β‐Spectrin and Karst. These results indicate that Spectrins are required for controlling photoreceptor morphogenesis through the modulations of cell membrane domains. genesis 47:744–750, 2009. © 2009 Wiley‐Liss, Inc.