title: The Xenopus laevis morphogenetic factor, tumorhead, causes defects in polarized growth and cytokinesis in the fission yeast, Schizosaccharomyces pombe.
abstract: Tumorhead (TH) is a maternally expressed gene product that regulates neural tube morphogenesis in the amphibian, Xenopus laevis. Here we describe the effects of TH expression in the rod-shaped fission yeast, Schizosaccharomyces pombe. Expression of TH in S. pombe resulted in severe morphological defects, including ovoid, bottle-shaped, and enlarged cells. Multi-septated cells were also observed in TH expressing cultures, indicating that TH is inhibitory to a process required for the completion of cytokinesis. TH expression caused significant actin and microtubule cytoskeletal defects, including depolarization of the cortical F-actin cytoskeleton and increased microtubule formation. Immunostaining experiments showed that TH is localized to the cell cortex, cell tips, and septum in S. pombe cells. Localization of TH to the cell cortex was dependent on the S. pombe PAK homolog, Shk1. Moreover, TH expression was inhibitory to the growth of a mutant defective in Shk1 function, suggesting that TH may interact with a component(s) of a PAK-mediated morphogenetic regulatory pathway in S. pombe. Taken together, our findings demonstrate that S. pombe may be a useful model organism for identifying potential TH interacting factors.
authors.affiliation: Department of Molecular Genetics and Program in Genes and Development, University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA.
authors.forename: Chuan Fen
authors.initials: CF
authors.lastname: Wu
authors.forename: Peirong
authors.initials: P
authors.lastname: Yang
authors.forename: Edwin E
authors.initials: EE
authors.lastname: Traverso
authors.forename: Laurence D
authors.initials: LD
authors.lastname: Etkin
authors.forename: Stevan
authors.initials: S
authors.lastname: Marcus
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D016764:Cell Polarity / Q000502:physiology*; D048749:Cytokinesis / Q000502:physiology*; D003599:Cytoskeleton / Q000378:metabolism; D015870:Gene Expression; D036341:Intercellular Signaling Peptides and Proteins / Q000502:physiology; D008870:Microtubules / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012568:Schizosaccharomyces / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000502:physiology; D029867:Xenopus Proteins; D014982:Xenopus laevis
chemical_list: D000199:Actins; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; D029702:Schizosaccharomyces pombe Proteins; D029867:Xenopus Proteins; C437083:trhd protein, Xenopus; D017346:Protein Serine-Threonine Kinases