title: Kinesin II is required for cell survival and adherens junction positioning in Drosophila photoreceptors.
abstract: Photoreceptor morphogenesis requires specific and coordinated localization of junctional markers at different stages of development. Here, we provide evidence that Drosophila Klp64D, a homolog of Kif3A motor subunit of the heterotrimeric Kinesin II complex, is essential for viability of developing photoreceptors and localization of junctional proteins. Genetic analysis of mutant clones shows that absence of Klp64D protein in early larval eye disc does not affect initial differentiation, but results in abnormal nuclear position in differentiating photoreceptors. These cells eventually die in the pupal stage, indicating klp64D's role in cell viability. The function of Klp64D protein is cell type specific because the p35 cell death inhibitor can rescue cell death in cone cells but not photoreceptors. In contrast to early induction of mutant clones, late induction during third instar larval stage just prior to pupation allows survival of single- or few-celled clones of klp64D mutant cells. Analysis of these lately induced clones shows that Klp64D function is essential for Bazooka (Par-3 homolog) and Armadillo localization to the adherens junction (AJ) in pupal photoreceptors. These findings suggest that Kinesin II complex plays a cell type-specific function in the localization of AJ and cell polarity proteins in the developing retina, thereby contributing to photoreceptor morphogenesis.
authors.affiliation: Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Bibhash
authors.initials: B
authors.lastname: Mukhopadhyay
authors.forename: Sang-Chul
authors.initials: SC
authors.lastname: Nam
authors.forename: Kwang-Wook
authors.initials: KW
authors.lastname: Choi
mesh_terms: D022005:Adherens Junctions / Q000502:physiology*; D000818:Animals; D051186:Armadillo Domain Proteins / Q000378:metabolism; D016764:Cell Polarity / Q000502:physiology*; D002470:Cell Survival / Q000502:physiology; D003001:Cloning, Molecular; D004330:Drosophila / Q000378:metabolism / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D016547:Kinesins / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009024:Morphogenesis / Q000502:physiology*; D017956:Photoreceptor Cells, Invertebrate / Q000378:metabolism / Q000502:physiology*; D011679:Pupa / Q000378:metabolism / Q000502:physiology; D014157:Transcription Factors / Q000378:metabolism
chemical_list: C495305:ARM protein, Drosophila; D051186:Armadillo Domain Proteins; D029721:Drosophila Proteins; D047908:Intracellular Signaling Peptides and Proteins; D014157:Transcription Factors; C400774:baz protein, Drosophila; C486143:KLP64D protein, Drosophila; D016547:Kinesins