title: TAC-1, a regulator of microtubule length in the C. elegans embryo.
abstract: Regulation of microtubule growth is critical for many cellular processes, including meiosis, mitosis, and nuclear migration. We carried out a genome-wide RNAi screen in Caenorhabditis elegans to identify genes required for pronuclear migration, one of the first events in embryogenesis requiring microtubules. Among these, we identified and characterized tac-1 a new member of the TACC (Transforming Acidic Coiled-Coil) family [1]. tac-1(RNAi) embryos exhibit very short microtubules nucleated from the centrosomes as well as short spindles. TAC-1 is initially enriched at the meiotic spindle poles and is later recruited to the sperm centrosome. TAC-1 localization at the centrosomes is regulated during the cell cycle, with high levels during mitosis and a reduction during interphase, and is dependent on aurora kinase 1 (AIR-1), a protein involved in centrosome maturation. tac-1(RNAi) embryos resemble mutants of zyg-9, which encodes a previously characterized centrosomal protein of the XMAP215 family and was also found in our screen. We show that TAC-1 and ZYG-9 are dependent on one another for their localization at the centrosome, and this dependence suggests that they may function together as a complex. We conclude that TAC-1 is a major regulator of microtubule length in the C. elegans embryo.
authors.affiliation: Wellcome Trust/Cancer Research UK Institute for Developmental Biology, Tennis Court Road, CB2 1QR, Cambridge, United Kingdom.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Le Bot
authors.forename: Miao Chih
authors.initials: MC
authors.lastname: Tsai
authors.forename: Robert K
authors.initials: RK
authors.lastname: Andrews
authors.forename: Julie
authors.initials: J
authors.lastname: Ahringer
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology*; D018385:Centrosome / Q000378:metabolism; D020869:Gene Expression Profiling; D015698:Genomic Library; D008297:Male; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D022101:Microtubule-Organizing Center / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D009687:Nuclear Proteins; D034622:RNA Interference; D013094:Spermatozoa / Q000166:cytology; D015534:Trans-Activators / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; C083728:MHC class II transactivator protein; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D015534:Trans-Activators; C112750:ZYG-9 protein, C elegans