title: Acquisition of cell polarity during cell cycle and oral replacement in Tetrahymena.
abstract: The aim of this study was to search for a mechanism responsible for the acquisition of cell polarity in a ciliate Tetrahymena. Homologs of the mammalian genes coding for CDC42-GSK3beta- MARK/PAR1-MAPs proteins were found in the Tetrahymena genome (Eisen et al., 2006, and this study). These proteins belong to a pathway which controls assembly and disassembly of microtubule bundles and cell polarity in neural cells. In Tetrahymena, there are two types of morphogenesis: divisional and oral replacement (OR). In divisional morphogenesis, an elongation of longitudinal microtubule bundles (LMs) takes place during cell division. In contrast, in OR type morphogenesis, which occurs in starved non-dividing cells, a polar retraction of LMs occurs. In T. pyriformis, the frequency of developmental switch to OR morphogenesis increases in the presence of wortmannin, an inhibitor of the CDC42-GSK3beta-MARK pathway. In contrast, wortmannin when applied to dividing cells does not affect divisional morphogenesis. Using immunostaining with the antibody against mammalian mitotic phosphoproteins (MPM-2) we show that these proteins co-localize with the LMs and are distributed along the anterior-posterior gradient. In addition, we show that during OR type morphogenesis, the fate of LMs correlates with the anterior-posterior gradient of instability of the cortical structures. We used the conditional mouth-less mutant of T. thermophila (Tiedtke et al., 1988) to test if the presence of the oral apparatus is required for the maintenance of cell polarity. We discuss our results in relation to the hypothesis of GSK3-beta-MARK pathway involvement in the acquisition of cell polarity in Tetrahymena.
authors.affiliation: Department of Cytophysiology, Institute of Zoology, Warsaw University, Warsaw, Poland. kaczan@biol.uw.edu.pl
authors.forename: Janina
authors.initials: J
authors.lastname: Kaczanowska
authors.forename: Szymon
authors.initials: S
authors.lastname: Kaczanowski
authors.forename: Mauryla
authors.initials: M
authors.lastname: Kiersnowska
authors.forename: Hanna
authors.initials: H
authors.lastname: Fabczak
authors.forename: Karolina
authors.initials: K
authors.lastname: Tulodziecka
authors.forename: Andrzej
authors.initials: A
authors.lastname: Kaczanowski
mesh_terms: D000595:Amino Acid Sequence; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D002453:Cell Cycle / Q000502:physiology*; D016764:Cell Polarity; D003599:Cytoskeleton / Q000378:metabolism; D018503:Genome, Protozoan; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules; D008969:Molecular Sequence Data; D009024:Morphogenesis; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D015800:Protozoan Proteins / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D016808:Tetrahymena thermophila / Q000166:cytology* / Q000235:genetics; D000077191:Wortmannin; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism
chemical_list: D000730:Androstadienes; D008869:Microtubule-Associated Proteins; D047428:Protein Kinase Inhibitors; D015800:Protozoan Proteins; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3; D020764:cdc42 GTP-Binding Protein; D000077191:Wortmannin