title: EMB-30: an APC4 homologue required for metaphase-to-anaphase transitions during meiosis and mitosis in Caenorhabditis elegans.
abstract: Here we show that emb-30 is required for metaphase-to-anaphase transitions during meiosis and mitosis in Caenorhabditis elegans. Germline-specific emb-30 mutant alleles block the meiotic divisions. Mutant oocytes, fertilized by wild-type sperm, set up a meiotic spindle but do not progress to anaphase I. As a result, polar bodies are not produced, pronuclei fail to form, and cytokinesis does not occur. Severe-reduction-of-function emb-30 alleles (class I alleles) result in zygotic sterility and lead to germline and somatic defects that are consistent with an essential role in promoting the metaphase-to-anaphase transition during mitosis. Analysis of the vulval cell lineages in these emb-30(class I) mutant animals suggests that mitosis is lengthened and eventually arrested when maternally contributed emb-30 becomes limiting. By further reducing maternal emb-30 function contributed to class I mutant animals, we show that emb-30 is required for the metaphase-to-anaphase transition in many, if not all, cells. Metaphase arrest in emb-30 mutants is not due to activation of the spindle assembly checkpoint but rather reflects an essential emb-30 requirement for M-phase progression. A reduction in emb-30 activity can suppress the lethality and sterility caused by a null mutation in mdf-1, a component of the spindle assembly checkpoint machinery. This result suggests that delaying anaphase onset can bypass the spindle checkpoint requirement for normal development. Positional cloning established that emb-30 encodes the likely C. elegans orthologue of APC4/Lid1, a component of the anaphase-promoting complex/cyclosome, required for the metaphase-to-anaphase transition. Thus, the anaphase-promoting complex/cyclosome is likely to be required for all metaphase-to-anaphase transitions in a multicellular organism.
authors.affiliation: Department of Cell Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
authors.forename: T
authors.initials: T
authors.lastname: Furuta
authors.forename: S
authors.initials: S
authors.lastname: Tuck
authors.forename: J
authors.initials: J
authors.lastname: Kirchner
authors.forename: B
authors.initials: B
authors.lastname: Koch
authors.forename: R
authors.initials: R
authors.lastname: Auty
authors.forename: R
authors.initials: R
authors.lastname: Kitagawa
authors.forename: A M
authors.initials: AM
authors.lastname: Rose
authors.forename: D
authors.initials: D
authors.lastname: Greenstein
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000705:Anaphase / Q000502:physiology; D064173:Anaphase-Promoting Complex-Cyclosome; D000818:Animals; D064192:Apc4 Subunit, Anaphase-Promoting Complex-Cyclosome; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008025:Ligases / Q000235:genetics*; D008677:Metaphase / Q000502:physiology; D008969:Molecular Sequence Data; D009154:Mutation; D009865:Oocytes / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D043743:Ubiquitin-Protein Ligase Complexes; D044767:Ubiquitin-Protein Ligases
chemical_list: D064192:Apc4 Subunit, Anaphase-Promoting Complex-Cyclosome; C577495:CDC20 protein, S cerevisiae; D029742:Caenorhabditis elegans Proteins; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D029701:Saccharomyces cerevisiae Proteins; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D044767:Ubiquitin-Protein Ligases; D008025:Ligases