Oogenesis in <i>Xenopus laevis</i> (Daudin). V. Relationships between developing oocytes and their investing follicular tissues

Dumont, James N.; Brummett, Anna Ruth

doi:10.1002/jmor.1051550106

Cited by 128 publications

(69 citation statements)

References 41 publications

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“…Since the serum factor is a macromolecule, the enveloping epithelial and follicular cells might be expected to provide a barrier to its diffusion to the receptors located in the oocyte plasma membrane. However, this does not seem to be the full explanation, because the epithelial cell envelope was open at the point where the follicle had been attached to the ovary, and the follicular cells do not completely cover the oocyte (10,33). Thus, it is probable that defolliculation of the oocyte, either manually or by collagenase treatment, leads to a greatly increased sensitivity to the serum factor.…”

Section: Discussionmentioning

confidence: 99%

A serum factor that activates the phosphatidylinositol phosphate signaling system in Xenopus oocytes.

Tigyi

Dyer

Matute

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

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Blood sera from many vertebrate species elicit large oscillatory chloride currents in oocytes from the frog Xenopus laevis. Rabbit serum was active at dilutions as great as one part in 10 million. Intracellularly applied serum was ineffective, and externally applied serum failed to trigger oscillatory currents when the intracellular level of ionized calcium was prevented from rising by loading the oocyte with EGTA. The serum also caused an increase of inositol 1,4,5-trisphosphate in the oocyte. We conclude that serum contains a factor which activates a membrane receptor that is coupled to the phosphatidylinositol second messenger system. The active factor is a protein with an apparent molecular mass of 60-70 kDa in gel permeation chromatography. Although the normal function of the serum factor is still unknown, it may have far-reaching implications, because it acts on the multifunctional phosphatidylinositol phosphate signaling system. Also, because of its great potency the serum factor and Xenopus oocytes are very useful for probing the operation of the phosphatidylinositol system.

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Section: Discussionmentioning

confidence: 99%

A serum factor that activates the phosphatidylinositol phosphate signaling system in Xenopus oocytes.

Tigyi

Dyer

Matute

et al. 1990

Proc. Natl. Acad. Sci. U.S.A.

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“…Electrophysiology was usually performed over the first 3 days of storage using methods described (2). Except where indicated, membrane currents were recorded from the voltage clamped oocyte still surrounded by its follicular envelope, theca, and ovarian epithelia (an ovarian follicle) (16). Crude pituitary preparations ofporcine (p) follicle-stimulating hormone (FSH), and human chorionic gonadotropin (hCG), isolated from urine, were purchased from Calbiochem and Sigma, respectively.…”

Section: Methodsmentioning

confidence: 99%

Hormonal activation of ionic currents in follicle-enclosed Xenopus oocytes.

Woodward¹,

Miledi²

1987

Proc. Natl. Acad. Sci. U.S.A.

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Membrane currents were recorded, using the voltage clamp technique, from Xenopus laevis oocytes still surrounded by their enveloping follicular and epithelial cells. Exposure of the follicles to mammalian gonadotropins elicited a current generated largely by an increase in membrane K' conductance. The gonadotropin response resembled responses elicited by adenosine and catecholamines in the same follicle, but was not blocked by purinergic or catecholaminergic antagonists. The gonadotropin-induced currents were potentiated by the adenylate cyclase activator forskolin and by phosphodiesterase inhibitors; similar currents were elicited in the same follicle by intraoocyte injection of cAMP, which indicates a role for this second messenger in the response mechanism. Gonadotropin responses were either abolished or substantially reduced after treatments that remove the ovarian epithelial and follicular cells. Our experiments suggest that the gonadotropin receptors, and the K+ channels they regulate, reside in the follicular cells.

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“…In view of these findings, the exact 85 mode of envelope synthesis during oogenesis merits investigation. A possible contribution of follicle cells for production and release of CE materials during oogenesis was emphasized on the basis of both TEM and SEM observations (4). More recent TEM observations by Pinto et a/.…”

Section: Introductionmentioning

confidence: 99%

The Synthesis and Localization of Envelope Glycoproteins in Oocytes of Xenopus laevis using Immunocytochemical Methods

1989

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Development Growth & DifferentiationThe site of origin and the mode of differentiation of the coelomic envelope (CE) in growing oocytes of Xenopus laevis were studied using the rabbit antiserum raised against the isolated envelope from oviposited eggs. The antiserum preabsorbed with egg extracts reacted with most components of CE glycoproteins detectable by SDS-PAGE, and stained specifically the CE of full-grown (st. VI) oocytes using indirect immunofluorescence methods. Transmission electron microscopy employing IgG-conjugated colloidal gold demonstrated that the CE antigens were distributed throughout the whole cytoplasm of st. I oocytes, and began to be deposited around the oocyte surface at late st. I. During st. II to VI the density of CE antigens in the oocyte cytoplasm decreased markedly, while the deposition of extracellular CE antigens increased gradually in association with the formation of a fibrillar network. The CE antigens were observed in and around the highly extended oocyte microvilli during st. II to IV, but were never found in follicle cells at any stages of oocyte growth. On western blot analyses, the extracellular CE components appeared first at st. II, and increased both in amount and number of bands during st. Ill -V to attain a typical electrophoretic profiles of well-developed CE. The cytosols of growing oocytes, however, possessed several antigenic components which were distinct from those of extracellular CE, suggesting the occurrence of intracellular precursor molecules for CE. The CEs of st. IV oocytes defolliculated and cultured in [3H] leucine contained certain CE components that expressed the radiolabel on fluorography. These results indicate that in Xenopus laevis the oocyte is directly involved in the synthesis and assembly, as well as secretion of CE with least contribution by the follicle cells.

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Oogenesis in Xenopus laevis (Daudin). V. Relationships between developing oocytes and their investing follicular tissues

Cited by 128 publications

References 41 publications

A serum factor that activates the phosphatidylinositol phosphate signaling system in Xenopus oocytes.

A serum factor that activates the phosphatidylinositol phosphate signaling system in Xenopus oocytes.

Hormonal activation of ionic currents in follicle-enclosed Xenopus oocytes.

The Synthesis and Localization of Envelope Glycoproteins in Oocytes of Xenopus laevis using Immunocytochemical Methods

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