Pyriform cell differentiation in Podarcis sicula is accompanied by the appearance of surface glycoproteins bearing α‐galNAc terminated chains

Andreuccetti, Piero; Famularo, Ciro; Gualtieri, Roberto; Prisco, Marina

doi:10.1002/ar.1070.abs

Cited by 3 publications

(6 citation statements)

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“…In conclusion, although it is not possible to draw final conclusions about the meaning of the described labeling pattern of DBA and the other tested lectins, the present data corroborate our previous data (Andreuccetti et al, 2001) that, unlike what happens in mammals (Shalgi et al, '91;Aviles et al, 2000), follicle cells in squamate reptiles expose sugar residues, whose distribution may undergo remarkable changes, in relation to the modifications of the follicular epithelium.…”

Section: Discussionsupporting

confidence: 85%

“…The small cells located under the basal lamina or intermingled among the pyriform cells are always negative, as well as the follicle cells surrounding the vitellogenic oocytes. It is interesting to note that the temporal and spatial distribution of DBA binding sites over the different follicle cells during the previtellogenesis and vitellogenesis in Podarcis muralis and Lacerta viridis is similar to that described in Podarcis sicula (Andreuccetti et al, 2001).…”

Section: Discussionsupporting

confidence: 57%

“…

ABSTRACTThe present investigation demonstrates that in squamate reptiles, as already reported for Podarcis sicula (Andreuccetti et al, 2001), the differentiation of pyriform cells from small, stem follicle cells is characterized by the progressive appearance on the cell surface of glycoproteins bearing α-GalNAc terminated O-linked side chains. Using a lectin panel (WGA, GSI-A4, GSI-B4, PSA UEA-I, PNA, Con-A, DBA, LCA, BPA, SBA), we demonstrated that, during previtellogenesis, the pattern of distribution of DBA binding sites over the follicular epithelium dramatically changes.

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confidence: 77%

“…In Podarcis sicula, the differentiation of small cells into pyriforms is accompanied by the appearance of glycoproteins bearing α-GalNAc terminated O-linked side chains on the cell surface (Andreuccetti et al, 2001). It was evidentiated that binding sites for DBA, specific for α-GalNAc terminated chains, significantly change during follicle growth.…”

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confidence: 99%

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Surface glycoproteins bearing α‐GalNAc terminated chains accompany pyriform cell differentiation in lizards

et al. 2001

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The present investigation demonstrates that in squamate reptiles, as already reported for Podarcis sicula (Andreuccetti et al., 2001), the differentiation of pyriform cells from small, stem follicle cells is characterized by the progressive appearance on the cell surface of glycoproteins bearing alpha-GalNAc terminated O-linked side chains. Using a lectin panel (WGA, GSI-A4, GSI-B4, PSA UEA-I, PNA, Con-A, DBA, LCA, BPA, SBA), we demonstrated that, during previtellogenesis, the pattern of distribution of DBA binding sites over the follicular epithelium dramatically changes. In fact, binding sites first appear in follicular epithelium at the time that small cells begin to differentiate; in such follicles, labeling is evident on the cell surfaces of small and intermediate cells. Later on, as the differentiation progresses, the binding sites also become evident on the cell surface of pyriform cells. Once differentiated, the pattern of the distribution of DBA binding sites over the follicular epithelium does not change. By contrast, during the phase of intermediate and pyriform cell regression, DBA binding sites gradually decrease, so that the monolayered follicular epithelium of vitellogenic follicles, constituted only by small cells, shows no binding sites for DBA. It is noteworthy that binding sites for DBA are present on small cells located in contact with the oocyte membrane, but not on those located under the basal lamina or among pyriform cells, and therefore not engaged in the differentiation into pyriform cells. This finding demonstrates that, in squamates, the pattern of distribution of alpha-N-GalNAc containing glycoproteins significantly changes during previtellogenesis, and that these modifications are probably related to the differentiation of small stem cells into highly specialized pyriforms.

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Section: Discussionsupporting

confidence: 85%

Section: Discussionsupporting

confidence: 57%

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Surface glycoproteins bearing α‐GalNAc terminated chains accompany pyriform cell differentiation in lizards

et al. 2001

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“…Lysis observed in the apex of follicular cells evinces the release of material into the zona pellucida. Andreuccetti and Carrera (1987) and Andreuccetti et al (2001) found that the oocyte and the follicle cells work together to synthesize and release components that give rise to the zona pellucida in the lizards Tarentola mauritanica and Podarcis sicula. In these lizards, as in Mabuya, the components of the zona pellucida consist of fibrils and amorphous electron-dense material that it is released into the intercellular space, forming initially patches that merge together to form a continuous coat around the oocyte.…”

Section: Follicular Epitheliummentioning

confidence: 99%

Ultrastructure of the ovarian follicles in the placentotrophic Andean lizard of the genus Mabuya (Squamata: Scincidae)

Vieira

Pérez

Ramírez‐Pinilla

2010

Journal of Morphology

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We studied the ultrastructural organization of the ovarian follicles in a placentotrophic Andean lizard of the genus Mabuya. The oocyte of the primary follicle is surrounded by a single layer of follicle cells. During the previtellogenic stages, these cells become stratified and differentiated in three cell types: small, intermediate, and large globoid, non pyriform cells. Fluid-filled spaces arise among follicular cells in late previtellogenic follicles and provide evidence of cell lysis. In vitellogenic follicles, the follicular cells constitute a monolayered granulosa with large lacunar spaces; the content of their cytoplasm is released to the perivitelline space where the zona pellucida is formed. The oolemma of younger oocytes presents incipient short projections; as the oocyte grows, these projections become organized in a microvillar surface. During vitellogenesis, cannaliculi develop from the base of the microvilli and internalize materials by endocytosis. In the juxtanuclear ooplasm of early previtellogenic follicles, the Balbiani's vitelline body is found as an aggregate of organelles and lipid droplets; this complex of organelles disperses in the ooplasm during oocyte growth. In late previtellogenesis, membranous organelles are especially abundant in the peripheral ooplasm, whereas abundant vesicles and granular material occur in the medullar ooplasm. The ooplasm of vitellogenic follicles shows a peripheral band constituted by abundant membranous organelles and numerous vesicular bodies, some of them with a small lipoprotein core. No organized yolk platelets, like in lecithotrophic reptiles, were observed. Toward the medullary ooplasm, electron-lucent vesicles become larger in size containing remains of cytoplasmic material in dissolution. The results of this study demonstrate structural similarities between the follicles of this species and other Squamata; however, the ooplasm of the mature oocyte of Mabuya is morphologically similar to the ooplasm of mature oocytes of marsupials, suggesting an interesting evolutionary convergence related to the evolution of placentotrophy and of microlecithal eggs.

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α and β spectrin distribution during the differentiation of pyriform cells in follicles of lizard Podarcis sicula

Ricchiari

Vaccaro

Prisco

et al. 2003

Molecular Reproduction Devel

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Using alpha and beta spectrin mammalian antibodies on Western blotting, we demonstrated that lizard ovarian follicles contain two isoforms of alpha spectrin, Mr 94 and 134 kDa, and a 230 kDa beta spectrin, and that their pattern modifies in relation to pyriform cell differentiation. In fact, a positive immunoreaction is firstly evident within follicular epithelium of previtellogenic follicles when small cells differentiate into pyriform cells via intermediate cells. Later on, immunostain is present in pyriform cells and in the oocyte cortex that previously appears unstained. It is noteworthy that immunostain is also present on small cells located in contact with the oocyte membrane, but not on those located under the basal lamina and among pyriform cells, not engaged in pyriform cell differentiation. During the subsequent stages of previtellogenic phase, spectrin immunostain over the follicular epithelium and in the oocyte cortex does not change. By contrast, in vitellogenic follicles, when the follicular epithelium is constituted only by small cells, immunostain is evident at the level of the oocyte cortex and the cytoplasm of regressing pyriform cells. The present data strongly suggest that the alpha and beta spectrin pattern put in evidence during the different phases of lizard oocyte growth is related to the differentiation of small into pyriform cells, where such protein may guarantee a relationship between surface glycoproteins (Andreuccetti et al., 2001: Anat Rec 263:1-9), and the cytoskeleton distribution (Maurizii et al., 2000: Raf Mol Reprod Dev 57:159-166). Furthermore, the distribution of spectrin mRNA, similar to that observed for the protein, demonstrates that spectrin, once synthesized within pyriform cells, is transferred through intercellular bridges in the oocyte cortex, thus confirming that pyriform cells are nurse that significantly are involved in the oocyte growth. Finally, the present data demonstrate that alpha spectrin of lizard ovarian follicles has Mr quite different from those so far reported and may constitute a new group of isoforms. This important result will be the focus of future experiments. Mol. Reprod. Dev. 67: 101-107, 2004.

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Pyriform cell differentiation in Podarcis sicula is accompanied by the appearance of surface glycoproteins bearing α‐galNAc terminated chains

Cited by 3 publications

References 10 publications

Surface glycoproteins bearing α‐GalNAc terminated chains accompany pyriform cell differentiation in lizards

Surface glycoproteins bearing α‐GalNAc terminated chains accompany pyriform cell differentiation in lizards

Ultrastructure of the ovarian follicles in the placentotrophic Andean lizard of the genus Mabuya (Squamata: Scincidae)

α and β spectrin distribution during the differentiation of pyriform cells in follicles of lizard Podarcis sicula

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