Spatial pattern of nonmuscle myosin-II distribution during the development of the Drosophila compound eye and implications for retinal morphogenesis.
Nonmuscle myosin-II is a motor protein that drives cell movement and changes in cell shape during tissue and organ development. This study has determined the dynamic changes in myosin-II distribution during Drosophila compound eye morphogenesis. In photoreceptor neurons, myosin-II is undetectable at the apical domain throughout the first half of pupal life, at which time this membrane domain is involuted into the epithelium and progresses toward the retinal floor. Myosin-II is deployed at the apical surface at about 60% of pupal development, once the developing rhabdomeres reach the retinal floor. Subsequently, myosin-II becomes restricted to two stripes at the sides of the developing rhabdomere, adopting its final position within the visual cells R1-6; here, myosin-II is associated with a set of actin filaments that extend alongside the rhabdomeres. At the midpupal stage, myosin-II is also incorporated into stress-fiber-like arrays within the basal endfeet of the pigment cells that then change their shape. This spatiotemporal pattern of myosin-II localization and the morphological defects observed in the eyes of a myosin-II mutant suggest that the myosin-II/F-actin system is involved in the alignment of the rhabdomeres within the retina and in the flattening of the retinal floor. The observation that the myosin-II/F-actin arrays are incomplete or disorganized in R7/R8 and in rhodopsin-1-null R1-6 suggests further that the establishment and stability of this cytoskeletal system depend on rhodopsin-1 expression.
Baumann
Otto
O
Institut für Biochemie und Biologie, Zoophysiologie, Universität Potsdam, D-14415 Potsdam, Germany. obaumann@rz.uni-potsdam.de
D000199:Actins / Q000032:analysis; D000818:Animals; D004330:Drosophila / Q000196:embryology*; D009024:Morphogenesis; D024462:Myosin Type II / Q000032:analysis* / Q000502:physiology; D010786:Photoreceptor Cells / Q000737:chemistry; D012160:Retina / Q000196:embryology*; D012243:Rhodopsin / Q000502:physiology
D000199:Actins; D012243:Rhodopsin; D024462:Myosin Type II