title: Drosophila klarsicht has distinct subcellular localization domains for nuclear envelope and microtubule localization in the eye.
abstract: The Drosophila klarsicht (klar) gene is required for developmentally regulated migrations of photoreceptor cell nuclei in the eye. klar encodes a large ( approximately 250 kD) protein with only one recognizable amino acid sequence motif, a KASH (Klar, Anc-1, Syne-1 homology) domain, at its C terminus. It has been proposed that Klar facilitates nuclear migration by linking the nucleus to the microtubule organizing center (MTOC). Here we perform genetic and immunohistochemical experiments that provide a critical test of this model. We analyze mutants in the endogenous klar gene and also flies that express deleted forms of Klar protein from transgenes. We find that the KASH domain of Klar is critical for perinuclear localization and for function. In addition, we find that the N-terminal portion of Klar is also important for function and contains a domain that localizes the protein to microtubules apical to the nucleus. These results provide strong support for a model in which Klar links the nucleus to the MTOC.
authors.affiliation: Section of Molecular Cell and Developmental Biology, Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712, USA. jaf@mail.utexas.edu
authors.forename: Janice A
authors.initials: JA
authors.lastname: Fischer
authors.forename: Shelley
authors.initials: S
authors.lastname: Acosta
authors.forename: Andrew
authors.initials: A
authors.lastname: Kenny
authors.forename: Courtney
authors.initials: C
authors.lastname: Cater
authors.forename: Christina
authors.initials: C
authors.lastname: Robinson
authors.forename: Jay
authors.initials: J
authors.lastname: Hook
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D005123:Eye / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D009685:Nuclear Envelope / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: D029721:Drosophila Proteins; D026901:Membrane Transport Proteins; C401521:klar protein, Drosophila