Microtubular spindle and centrosome structures during the cell cycle in a dinoflagellate Crypthecodinium cohnii B.: an immunocytochemical study

Perret, Eric; Albert, Marie; Bordes, Nicole; Bornens, Michel; Soyer‐Gobillard, Marie‐Odile

doi:10.1016/0303-2647(91)90012-a

Cited by 20 publications

(5 citation statements)

References 33 publications

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“…anti-actin/anti CTR 21OAb/DAPI and antiactin/anti-p72/DAPI Labellings were performed as decribed [59] using either the same polyclonal anti-p72 [59,61], or the monoclonal anti-CTR 210 [4] as second Ab and the anti-a-actin (Boehringer) as first Ab.…”

Section: Triple Labellingmentioning

confidence: 99%

“…One of the most striking results of this work was that the cortical microtubules do not depolymerize during mitosis when the mitotic microtubular spindle appears. The centrosome-like duplicated regions organize the formation of the labile extranuclear microtubular mitotic spindle, passing through the nucleus in cytoplasmic channels without any direct contact with the permanently condensed chromosomes within the nuclear envelope [45,59,83,901 which persists throughout the cell cycle (for a review, see [98]).…”

Section: Introductionmentioning

confidence: 99%

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Nuclear and cytoplasmic actin in dinoflagellates

Soyer‐Gobillard

Ausseil

Géraud

1996

Biology of the Cell

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Experiments using monoclonal and polyclonal anti-actin antibodies allowed us to demonstrate the presence of F- or G-actin in original protists, dinoflagellates, either by biochemistry, immunofluorescence and in TEM. SDS-PAGE electrophoresis and immunoblottings made either from total or nuclear protein extracts revealed the presence of a 44-kDa band reacting with monoclonal anti-actin antibody in two species, Prorocentrum micans and Crypthecodinium cohnii, and thus demonstrated the presence of actin in nuclear and cytoplasmic fractions. After squash preparation of P micans cells, actin was identified within the nucleus and in some regions of the cytoplasm by immunofluorescence microscopy. Labelling of both the nucleolus and the centrosome region was evident together with amorphous nucleoplasmic material surrounding the chromosomes. The use of cryosections of intact P micans and C cohnii cells for immunofluorescence along with staining with DAPI to delineate the chromosomes themselves, yielded finer resolution of the intranuclear network labelling pattern and allowed us to complete our observations, in particular on the cytoplasmic labelling. In P micans, in addition to the centrosome region, the cytoplasmic channels passing through the nucleus in dividing cells are labelled. In C cohnii, the cortex, the centrosome region, the cytoplasmic channels, the region surrounding the nucleus, the filaments linking it to the cortex and the cleavage furrow are also labelled. In the nucleus of the two species, there is a prominent "weft' of fine actin filaments in the nucleoplasm forming a matrix of varying density around the persistent chromosomes. This actin matrix, of unknown function, is most conspicuous at the end of the S-phase of the cell cycle. Fluorescent derivatives of phalloidin, used as diagnostic cytochemical probes for polymeric actin (F-actin), gave similar results. Positive TEM immunolabelling of intranuclear actin confirms its presence in the nucleoplasm, in the nucleolus where the preribosomal region is labelled while C cohnii chromosomes are unlabelled and the P micans chromosomes very slightly. In the cytoplasm, lips of the cleavage furrow and kinetosome regions are labelled as well as the centrosome region. The possible functions of this protein located in several compartments of dinoflagellate cells are discussed.

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Section: Triple Labellingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nuclear and cytoplasmic actin in dinoflagellates

Soyer‐Gobillard

Ausseil

Géraud

1996

Biology of the Cell

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“…Their mitosis, named dinomitosis by Chatton [4], differs considerably from the higher eukaryote mitosis; in particular, the nuclear envelope is present throughout the cell cycle, even during mito. sis; the mitotic microtubular spindle is totally extranuclear [17,24,34], and the segregation of the chromosomes is effected in direct contact with the nuclear envelope [17,37]. One of the most intersting characteristics concerns their chromosomes, which are permanently condensed throughout the cell cycle, with a twisted helicoidal organization of their nucleofilaments [13].…”

Section: Introductionmentioning

confidence: 99%

Immunocytochemical localization of the DNA‐binding protein HCc during the cell cycle of the histone‐less dinoflagellate protoctista Crypthecodinium cohnii B

Géraud

Sala-Rovira

Herzog

et al. 1991

Biology of the Cell

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Summary— The major basic nuclear protein HCc (previously named Histone‐like) of the dinoflagellate Crypthecodinium cohnii B was immunolocalized in light and electron microscopy using an affinity‐purified polyclonal antibody. Complementary conventional and cryo‐techniques were used to study the distribution of the DNA‐binding protein in interphase cells and to follow its behaviour throughout the mitotic cycle. In non‐dividing cells, the HCc protein was found to be located on extra‐chromosomal loops and chromosomal nucleofilaments dispersed in the nucleoplasm. In mitotic cells, from prophase to early telophase, it was homogeneously distributed in the (whole) dividing chromosomes. HCc protein was also detected in two compartments of all the permanently observable nucleoli: the nucleolar organizing region and the fibrillo‐granular region. In this paper we discuss the hypothetical roles, structural and/or functional, of this DNA‐binding protein, which is specific to dinoflagellates, the only eukaryotes whose chromatin is devoid of histones and nucleosomes.

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“…Antibodies are an essential tool in cell biology studies to identify and characterize proteins involved in diverse cellular processes (1–5). Classical production of antibodies has certain limitations that are inherent in the use of animal‐based production systems.…”

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confidence: 99%

Recombinant Antibodies Against Subcellular Fractions Used to Track Endogenous Golgi Protein Dynamics in Vivo

Nizak¹,

Lluesma

Moutel

et al. 2003

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Generation of specific antibodies against enriched subcellular fractions is a powerful strategy to identify and characterize cellular components. We show that recombinant antibodies can be selected in vitro by phage display against complex subcellular fractions, namely microtubule-binding proteins and Golgi stacks. This technique has allowed us to overcome many limitations of the classical animal-based approach and generate cell biology-compliant antibodies. In addition, we show that intracellular expression of GFP-tagged recombinant antibodies can reveal the dynamics of endogenous proteins in vivo. Endogenous Giantin is very static and outlines the Golgi in living cells. It accumulates neither onto Golgi-derived tubules upon Brefeldin A treatment before Golgi disappearance, nor onto de novo formed Golgi mini-stacks upon microtubule depolymerization, and remains instead on the 'old' pericentriolar Golgi. This suggests that, in contrast to other Golgi matrix proteins, endogenous Giantin is very stably associated with the Golgi and does not efficiently recycle to the ER. Altogether, we show that the antibody phage display technique represents an efficient alternative to rapidly generate versatile antibodies that represent new tools to study protein function.

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Microtubular spindle and centrosome structures during the cell cycle in a dinoflagellate Crypthecodinium cohnii B.: an immunocytochemical study

Cited by 20 publications

References 33 publications

Nuclear and cytoplasmic actin in dinoflagellates

Nuclear and cytoplasmic actin in dinoflagellates

Immunocytochemical localization of the DNA‐binding protein HCc during the cell cycle of the histone‐less dinoflagellate protoctista Crypthecodinium cohnii B

Recombinant Antibodies Against Subcellular Fractions Used to Track Endogenous Golgi Protein Dynamics in Vivo

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