The Epiplasm Gene EPC1 Influences Cell Shape and Cortical Pattern in Tetrahymena thermophila1

Williams, Norman E.

doi:10.1111/j.1550-7408.2004.tb00546.x

Cited by 26 publications

(29 citation statements)

References 25 publications

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“…Prior to cytokinesis, the LM-bands maintain their continuity until the fission line separates them. Eventually, after the cytokinesis, the apical band reforms (JerkaDziadosz et al, 2001;Thazhath et al, 2002;2004). Thus the parental cell undergoes continuous unidirectional elongation in the middle region of the parental cell with the local intercalation of basal bodies and the in situ addition of microtubular subunits into the LM-bands; the process which is consistent with Frankel's (1989) model of "the continuum growth cylinder".…”

supporting

confidence: 72%

“…2D-F). This was reminiscent of T. thermophila phenotypes observed in cells with the EPC1 gene (epiplasm C protein) gene knockout (Williams, 2004). This suggests (but does not prove) that during starvation of a wild type cells, or in mutants (mouth-less II8G and EPC1 knockout cells) the gradient of structural stability is present along the anterior-posterior axis of cells.…”

Section: Discussionmentioning

confidence: 78%

“…Full knockout of the EPC1 gene influences both cell shape and the fidelity of cortical development (Williams, 2004). Epi B protein is absent in the areas occupied by the oral apparatus, the LM-s, the all basal bodies and the contractile vacuole pores (Williams et al, 1990 (Fig.…”

Section: Abstract: Tetrahymena Polarity Cytoskeleton Mark Armadillomentioning

confidence: 99%

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Acquisition of cell polarity during cell cycle and oral replacement in Tetrahymena

Kaczanowska

Kaczanowski²,

Kiersnowska³

et al. 2008

Int. J. Dev. Biol.

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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-GSK3β-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-GSK3β-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 mouthless 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-β-MARK pathway involvement in the acquisition of cell polarity in Tetrahymena. KEY WORDS: Tetrahymena, polarity, cytoskeleton, MARK, armadilloThe Tetrahymena (like other ciliates) is a permanently polarized cell. Longitudinal ciliary rows (CR) define its anterior-posterior axis and a sub-apically located oral apparatus (OA) marks its ventral side. The position of other cortical structures depends on the position of the oral apparatus (Frankel 1999) (Fig. 1A and Fig. 7A). In Tetrahymena the spatial deployment of the cytoskeletal proteins is under genetic control of a mechanism of global positioning (Kaczanowski 1975, Williams et al., 1987, JerkaDziadosz et al., 1995, Kaczanowska et al., 2003, StrzyzewskaJowko et al., 2003. The aim of the present study was to gain an insight into the mechanism responsible for the acquisition and maintenance of cell polarity, during morphogenesis of Tetrahymena.In Tetrahymena there are two types of morphogenesis: divisional and oral replacement (OR). The cortex of Tetrahymena contains a regular array of polarized longitudinal microtubular Int. J. Dev. Biol. 52: 249-258 (2008) Abbreviations used in this paper: AF, anarchic field of oral primordium; CR, ciliary rows of basal body units; CVP, the contractile vacuole pore located at the posterior area of the cell to the right of the ventral side; EHT, end of heat treatment; LM, Longitudinal microtubule bands; nOA, newly formed oral apparatus that a...

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supporting

confidence: 72%

Section: Discussionmentioning

confidence: 78%

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Acquisition of cell polarity during cell cycle and oral replacement in Tetrahymena

Kaczanowska

Kaczanowski²,

Kiersnowska³

et al. 2008

Int. J. Dev. Biol.

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“…However, it is worth mentioning that a knockout of the gene coding for one of the three major membrane-skeletal proteins, EpiC (162,164), brought about a transient disruption of the organization of oral structures, accompanied by some disarray in the ciliary rows (158).…”

Section: The Mutationsmentioning

confidence: 99%

What Do Genic Mutations Tell Us about the Structural Patterning of a Complex Single-Celled Organism?

Frankel

2008

Eukaryot Cell

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PROLOGUE: FROM THE CYTOPLASM TO THE NUCLEUSStructural inheritance in the ciliate cortex. Ciliates make up a distinctive group of unicellular organisms characterized by dualism of germ line and somatic nuclei, sex by reciprocal exchange of gametic nuclei with subsequent replacement of the somatic nucleus, and an extraordinarily complex organization of the cell surface layer. This organization is dominated by cytoskeletal structures, including rows of basal bodies, cilia, and accessory fibrillar structures, and is perpetuated by longitudinal extension of these structural ensembles during clonal growth.This mode of perpetuation provides an ideal opportunity for the demonstration and analysis of cellular heredity at a nongenic level. This opportunity was seized by three gifted biologists, the comparative zoologist Emmanuel Fauré-Fremiet, the experimental embryologist Vance Tartar, and the geneticist Tracy Sonneborn, who together led the way in establishing the principle that structural variations of nongenic origin in the ciliate cortex can indeed be faithfully transmitted to progeny over numerous cell generations.Although this review is primarily devoted to the contribution of genic mutations to the understanding of the ciliate cortex, the interpretation of some of the more interesting of these mutations becomes more meaningful against a background of the three major arenas of nongenic structural inheritance in the ciliate cortex, all of which were solidly established before the genetic approach was initiated.The best-known form of structural inheritance is the organization of the longitudinal ciliary rows that cover the surfaces of most ciliates. This was first demonstrated by Beisson and Sonneborn (12), who showed that an inversion (180°rotation) of one or more ciliary rows of Paramecium tetraurelia (then Paramecium aurelia, syngen 4) (Fig. 1A) could be nongenically inherited; Sonneborn gave the name "cytotaxis" to "this ordering and arranging of new structures under the influence of pre-existing cell structure" (137). This demonstration was later repeated for Tetrahymena thermophila (then Tetrahymena pyriformis, syngen 1) (118) and for other ciliates (62,63,71). It was extended by Nanney's observation that the preexisting number of ciliary rows in T. thermophila tended to be conserved (103, 104), presumably due to the same structural constraints that conserve the geometrical organization of these rows.A second form of structural inheritance is demonstrated by the propagation of the number of complete sets of cortical structures. This was investigated in detail by 32), who noted that ciliates that became fused side by side, as a consequence of blockage of division followed by anterior sliding of the presumptive posterior daughter cell, could propagate their duality. Later, Vance Tartar (147) demonstrated that microsurgically constructed Siamese-twin doublets in the large ciliate Stentor coeruleus could perpetuate their doublet condition. In both cases, the way in which the doublets were created virtually rules o...

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“…The modal number of kineties differs in different ciliate species, known as their corticotype. For Tetrahymena thermophila, the best studied species, the corticotype exhibits a range of 19 -21 kineties with a stable modal Fibonacci number of twenty-one (21), when the truncated paroral kinety is included in the count [14]. Under natural condition of starvation, cells with a corticotype of 18 -19 kineties undergo oral replacement and insertion of two additional postoral kineties, resulting in the stable modal Fibonacci number of twenty-one (21) kineties, while cells with the stable Fibonacci number of 21 kineties are unaffected by these conditions [15].…”

Section: Eucaryotic Protozoamentioning

confidence: 99%

Occurrence of Fibonacci numbers in development and structure of animal forms: Phylogenetic observations and epigenetic significance

Wille¹

2012

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The Epiplasm Gene EPC1 Influences Cell Shape and Cortical Pattern in Tetrahymena thermophila¹

Cited by 26 publications

References 25 publications

Acquisition of cell polarity during cell cycle and oral replacement in Tetrahymena

Acquisition of cell polarity during cell cycle and oral replacement in Tetrahymena

What Do Genic Mutations Tell Us about the Structural Patterning of a Complex Single-Celled Organism?

Occurrence of Fibonacci numbers in development and structure of animal forms: Phylogenetic observations and epigenetic significance

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