Macronuclear differentiation in conjugating pairs of Tetrahymena treated with the antitubulin drug nocodazole*1

Kaczanowski, Andrzej; Ramel, Malgorzata; Kaczanowska, Janina; Wheatley, Denys N.

doi:10.1016/0014-4827(91)90381-4

Cited by 29 publications

(21 citation statements)

References 22 publications

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“…The protozoacidal activity of the analogues was found to be highly 25 dependent on a 4-hydroxyl group at the 6-aryl ring, and a chiral 1-phenylethanamine substituent in posi- 26 tion 4. Further, the potency was affected by the aromatic substitution pattern of the phenylethanamine: 27 the unsubstituted, the meta-fluoro and the para-bromo substituted derivatives had the lowest minimum 28 protozoacidal concentrations (8)(9)(10)(11)(12)(13)(14)(15)(16) lg/mL). Surprisingly, both enantiomers were found to have high 29 potency suggesting that this compound class could have several modes of action.…”

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confidence: 99%

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Activity of 6-aryl-pyrrolo[2,3-d]pyrimidine-4-amines to Tetrahymena

Kaspersen

Sundby²,

Charnock

et al. 2012

Bioorganic Chemistry

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confidence: 99%

“…The motility behaviour of Tetrahymena is conveniently used 52 to monitor bioactivity and cell toxicity of chemicals [13][14][15]. roquine [25] and Chloroamphenicol [26,27] and antineoplastics 67 such as Necodazole [28], Fig. 1.…”

mentioning

confidence: 99%

Activity of 6-aryl-pyrrolo[2,3-d]pyrimidine-4-amines to Tetrahymena

Kaspersen

Sundby²,

Charnock

et al. 2012

Bioorganic Chemistry

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“…Observations suggesting that time point have been made in Tetrahymena through the use of some inhibitors and spontaneous mutants. Neither blocking of the pronuclear exchange with nocodazole 73 nor of fertilization with vinblastine 74 affects the programs, in which development starts with haploid micronuclei. On the other hand, mixing with an amicronucleate mutant 75 or certain lines called “star” strains 76 , 77 abolishes conjugation in response to imperfections in meiosis events in the mutants.…”

Section: Discussionmentioning

confidence: 99%

Role of class III phosphatidylinositol 3-kinase during programmed nuclear death ofTetrahymena thermophila

et al. 2013

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Programmed nuclear death (PND) in the ciliate protozoan Tetrahymena thermophila is a novel type of autophagy that occurs during conjugation, in which only the parental somatic macronucleus is destined to die and is then eliminated from the progeny cytoplasm. Other coexisting nuclei, however, such as new micro- and macronuclei are unaffected. PND starts with condensation in the nucleus followed by apoptotic DNA fragmentation, lysosomal acidification, and final resorption. Because of the peculiarity in the process and the absence of some ATG genes in this organism, the mechanism of PND has remained unclear. In this study, we focus on the role of class III phosphatidylinositol 3-kinase (PtdIns3K, corresponding to yeast Vps34) in order to identify central regulators of PND. We identified the sole Tetrahymena thermophila ortholog (TtVPS34) to yeast Vps34 and human PIK3C3 (the catalytic subunit of PtdIns3K), through phylogenetic analysis, and generated the gene knockdown mutant for functional analysis. Loss of TtVPS34 activity prevents autophagosome formation on the parental macronucleus, and this nucleus escapes from the lysosomal pathway. In turn, DNA fragmentation and final resorption of the nucleus are drastically impaired. These phenotypes are similar to the situation in the ATG8Δ mutants of Tetrahymena, implying an inextricable link between TtVPS34 and TtATG8s in controlling PND as well as general macroautophagy. On the other hand, TtVPS34 does not appear responsible for the nuclear condensation and does not affect the progeny nuclear development. These results demonstrate that TtVPS34 is critically involved in the nuclear degradation events of PND in autophagosome formation rather than with an involvement in commitment to the death program.

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“…The paroral cortex exhibits the capacity to trap and anchor a selected nucleus following the second meiosis, and the posterior cortex appears to perform a similar function at the end of the second post‐zygotic nuclear division. In both cases, this nuclear‐cortical association appears to shield the nuclei involved from cytoplasmic signals that initiate nuclear degradation in the former case and macronuclear differentiation in the latter case (Kaczanowski et al 1991). Kaczanowski and Kiersnowska (1996) clearly demonstrated that the capacity to shield postzygotic nuclei from signals triggering macronuclear differentiation is still present in parabiotically fused (double‐posterior) conjugants.…”

Section: Discussionmentioning

confidence: 99%

The Role of Cortical Geometry in the Nuclear Development of Tetrahymena thermophila

Gaertig¹,

Cole²

2000

J Eukaryotic Microbiology

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Vegetative cells were subjected to electrofusion and the resulting heteropolar doublets were then mated to normal single cells and followed throughout conjugation using cytological and genetic techniques. The unique cyto-geometry created in a heteropolar doublet--a continuous cytoplasmic compartment bounded by two anterior poles and sharing a fused posterior pole at midbody, and the potential for two conjugal exchange junctions--resulted in instructive perturbations of nuclear behavior. Our results indicate that the course of nuclear development is strongly dependent on the cortical geometry of conjugating cells. Specifically, 1) continuation of development after meiosis requires an established conjugal junction; 2) after pronuclear exchange, pronuclei are subjected to attractive forces; and 3) products of the second postzygotic division are actively positioned near the posterior region of the cell cortex where they develop into micronuclei.

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Macronuclear differentiation in conjugating pairs of Tetrahymena treated with the antitubulin drug nocodazole*1

Cited by 29 publications

References 22 publications

Activity of 6-aryl-pyrrolo[2,3-d]pyrimidine-4-amines to Tetrahymena

Activity of 6-aryl-pyrrolo[2,3-d]pyrimidine-4-amines to Tetrahymena

Role of class III phosphatidylinositol 3-kinase during programmed nuclear death ofTetrahymena thermophila

The Role of Cortical Geometry in the Nuclear Development of Tetrahymena thermophila

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