title: A semi-dominant mutation in the general splicing factor SF3a66 causes anterior-posterior axis reversal in one-cell stage C. elegans embryos.
abstract: Establishment of anterior-posterior polarity in one-cell stage Caenorhabditis elegans embryos depends in part on astral microtubules. As the zygote enters mitosis, these microtubules promote the establishment of a posterior pole by binding to and protecting a cytoplasmic pool of the posterior polarity protein PAR-2 from phosphorylation by the cortically localized anterior polarity protein PKC-3. Prior to activation of the sperm aster, the oocyte Meiosis I and II spindles assemble and function, usually at the future anterior pole, but these meiotic spindle microtubules fail to establish posterior polarity through PAR-2. Here we show that a semi-dominant mutation in the general splicing factor SF3a66 can lead to a reversed axis of AP polarity that depends on PAR-2 and possibly on close proximity of oocyte meiotic spindles with the cell cortex. One possible explanation is that reduced levels of PKC-3, due to a general splicing defect, can result in axis reversal due to a failure to prevent oocyte meiotic spindle microtubules from interfering with AP axis formation.
authors.affiliation: Institute of Molecular Biology, University of Oregon, Eugene, Oregon, United States of America.
authors.forename: Mohammad R
authors.initials: MR
authors.lastname: Keikhaee
authors.affiliation: Institute of Molecular Biology, University of Oregon, Eugene, Oregon, United States of America.
authors.forename: Eric B
authors.initials: EB
authors.lastname: Nash
authors.affiliation: Institute of Molecular Biology, University of Oregon, Eugene, Oregon, United States of America.
authors.forename: Sean M
authors.initials: SM
authors.lastname: O'Rourke
authors.affiliation: Institute of Molecular Biology, University of Oregon, Eugene, Oregon, United States of America.
authors.forename: Bruce
authors.initials: B
authors.lastname: Bowerman
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics*; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D009154:Mutation; D017413:Ribonucleoprotein, U2 Small Nuclear / Q000235:genetics*
chemical_list: D029742:Caenorhabditis elegans Proteins; D017413:Ribonucleoprotein, U2 Small Nuclear; C088049:splicing factor 3a