How the ovarian follicle of Podarcis sicula recycles the DNA of its nurse, regressing follicle cells

De, Manisha; Indolfi, Paolo; Iodice, Carmela; Spagnuolo, S; Tammaro, S.; Motta, Chiara Maria

doi:10.1002/(sici)1098-2795(199812)51:4<421::aid-mrd9>3.3.co;2-w

Cited by 7 publications

(10 citation statements)

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“…mitochondria, ribosomes, vesicles and so on. In this regard, enlarged cells represent a type of nurse cell similar to those reported in squamate reptiles (Andreuccetti et al 1978;Motta et al 1995Motta et al , 2001De Caro et al 1998). Unlike reptiles, intermediate and pyriform cells in Torpedo transfer material to the oocyte also during the vitellogenic phase.…”

Section: Discussionsupporting

confidence: 54%

Oogenesis in the spotted ray Torpedo marmorata

Prisco

Liguoro

Ricchiari

et al. 2006

Rev Fish Biol Fisheries

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Investigation of embryos, neonates, sub-adult and adult female Torpedo marmorata showed that oogenesis is immediate. It begins very early in development and continues, in its proliferative phase after birth. In newborns, 3-4 month old, all germ cells present in the ovary have achieved diplotene stage and are surrounded by a single layer of small follicle cells (primordial follicles). Later with continued oocyte growth, the follicular epithelium (granulosa) progressively changes its organization and becomes multilayered and polymorphic with the presence of three types of cells: small, intermediate and pyriform cells. This organization lasts until the end of oocyte growth, but its activity changes significantly. Indeed, in the previtellogenic phase intermediate and pyriform-cells transfer to the oocyte mitochondria, ribosomes, vesicles, via intercellular bridges; during vitellogenesis, intermediate and pyriform cells, as well as small follicle cells, synthesize and transfer vitellogenin within the oocyte. During Torpedo oogenesis, in concomitance with the differentiation of the granulosa, the nucleolar apparatus is modified significantly: transcriptionally active in primary follicles, it becomes inactive during the subsequent stages of oocyte growth.

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Section: Discussionsupporting

confidence: 54%

Oogenesis in the spotted ray Torpedo marmorata

Prisco

Liguoro

Ricchiari

et al. 2006

Rev Fish Biol Fisheries

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“…Briefly, cells were obtained from the epithelia by vortexing (De Caro et al 1998), recovered by mild centrifugation and resuspended in a buffered solution containing 5 μg/ml MitoCapture for 15 min at 26°C under a 5% CO 2 atmosphere. Cells in suspension were washed and plated onto slides and observed under a Zeiss Axioskop microscope equipped with an UV lamp.…”

Section: Animalsmentioning

confidence: 99%

“…Pyriform cells were mechanically isolated from differentiating or remodelling epithelia (De Caro et al 1998) and aliquoted in samples containing 6×10 6 cells. Each aliquot was then homogenized in RIPA buffer (50 mM TRIS-HCl pH 7.4, 1% NP-40, 0.25% Na-deoxycholate, 150 mM NaCl, 1 mM EDTA, 1 mM phenylmethyl sulphonylfluoride, 1 μg/ml aprotinin, leupeptin and pepstatin, 1 mM Na 3 VO 4 , 1 mM NaF) and centrifuged at 14,000g for 15 min at 4°C.…”

Section: Immunoblottingmentioning

confidence: 99%

“…Differentiating and remodelling epithelia were dissociated by using the procedure described in De Caro et al (1998). Isolated cells were homogenized in five volumes of buffer A (20 mM HEPES-KOH pH 7.5, 10 mM KCl, 1.5 mM MgCl 2 , 1 mM NaEDTA, 1 mM EGTA, 1 mM dithiothreitole, 250 mM sucrose and 0.1 mM phenylmethyl sulphonyl-fluoride) at 4°C and centrifuged at 500g for 10 min.…”

Section: Preparation Of Mitochondrial and Cytosolic Fractions From Fomentioning

confidence: 99%

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Block of mitochondrial apoptotic pathways in lizard ovarian follicle cells as an adaptation to their nurse function

et al. 2006

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Pyriforms are ovarian follicle nurse cells that undergo apoptosis at the end of previtellogenesis and are completely eliminated by the epithelium. This event is accompanied by the active transfer of organelles and macromolecules to the oocyte via an intercellular bridge. Since it would be a nonsense for damaged mitochondria to reach the oocyte, we have postulated that pyriform cells have adapted their apoptotic machinery to prevent mitochondrial degradation. To verify this hypothesis, we have studied mitochondrial morphology and functionality during follicle cell regression. Cytological and biochemical evidence indicates that mitochondria in pyriforms maintain their size, organization and membrane potential. This clearly indicates that they are not involved in apoptosis signalling/progression. This block would favour both the oocyte, by increasing the pool of organelles available from follicle cells, and also the regressing pyriforms, by maintaining the energy resources required for completion of their nurse function. The block is probably attributable to an over-expression of Bcl-2 and might be carried out by sequestering cytochrome c inside the organelles. As demonstrated by in vitro experiments, the mitochondrial apoptosis pathway can be activated by stress induction, such as serum deprivation, but not following physiological pro-apoptotic signalling, such as treatment with gonadotrophin-releasing hormone.

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“…Fractions enriched in pyriform or small cells were prepared as described in De Caro et al (1998). Briefly, the epithelia were manually dissected from whole follicles and repeatedly vortexed to detach progressively the external small cells, the inner small cells and a few pyriforms and, finally, the pyriforms.…”

Section: Follicular Epithelium Dissociationmentioning

confidence: 99%

cGnRH II involvement in pyriform cell apoptosis

et al. 2008

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We have investigated whether gonadotrophin-releasing hormone (GnRH) is involved in triggering the apoptotic death of pyriforms, the nurse cells that cooperate in oocyte growth during mid- to late previtellogenesis in the lizard Podarcis sicula. Our immunocytochemical analyses demonstrate that pyriforms express GnRH receptors and that, in late previtellogenesis, they are up-regulated by cGnRH II. The hormone however does not trigger receptor synthesis and activation, events that therefore must be under the control of other regulatory factors. Our results also indicate that in vitro treatment of pyriforms with cGnRH II induces DNAse I activation and DNA laddering, clear cytological evidence of apoptosis, but not Fas/Fas-L synthesis or caspase activation. We conclude that cGnRH II is pro-apoptotic to pyriform cells and that it exerts its effects by activating an alternative cell death pathway, probably involving calcium as first messenger and DNase I as first executioner.

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How the ovarian follicle of Podarcis sicula recycles the DNA of its nurse, regressing follicle cells

Cited by 7 publications

References 0 publications

Oogenesis in the spotted ray Torpedo marmorata

Oogenesis in the spotted ray Torpedo marmorata

Block of mitochondrial apoptotic pathways in lizard ovarian follicle cells as an adaptation to their nurse function

cGnRH II involvement in pyriform cell apoptosis

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