Changes in cortical granules during porcine oocyte maturation

Cran, D. G.; Cheng, W. T. K.

doi:10.1002/mrd.1120110311

Cited by 48 publications

(45 citation statements)

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“…Cran et al [1] reported that 80% of CGs were distributed over the cortical cytoplasm in oocytes collected from antral follicles 20 hrs after hCG injection, while 20% were distributed immediately beneath the plasma membrane. The observation of Cran et al [1] convinced us that in vitro maturing oocytes, classified as type II in the present study, were in the transient period from type I to type III.…”

Section: Discussionmentioning

confidence: 99%

“…CGs are distributed over the cortical cytoplasm in the germinal vesicle (GV)-stage oocyte collected from antral follicles, and the CGs move to the cytoplasm immediately beneath the plasma membrane as maturation progresses [1][2][3][4]. In oocytes collected from antral follicles 20 hrs [1] or 24 to 36 hrs [2] after hCG injection and those cultured for 24 hrs [2] or 26 hrs [3,4], most CGs are observed immediately beneath the plasma membrane.…”

Section: Cortical Granule Distribution Lectin Histochemistry Olomoumentioning

confidence: 99%

“…Changes in cortical granule (CG) distribution with maturation have been studied in porcine oocytes under electron microscopy [1,2] and also histochemically with lectin [2][3][4]. CGs are distributed over the cortical cytoplasm in the germinal vesicle (GV)-stage oocyte collected from antral follicles, and the CGs move to the cytoplasm immediately beneath the plasma membrane as maturation progresses [1][2][3][4].…”

Section: Cortical Granule Distribution Lectin Histochemistry Olomoumentioning

confidence: 99%

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The Relationship between Nuclear Maturation and Cortical Granule Distribution in Cultured Porcine Oocytes

2002

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When porcine oocytes cultured for 26 hrs, in which CGs are distributed immediately beneath the plasma membrane, were inseminated, sperm penetration was observed in 98% of the oocytes, and 81% of those oocytes showed polyspermy, but only 26% of the o o c y t e s c o u l d c o m p l e t e l y r e l e a s e C G s a f t e r insemination [4]. Since a high frequency of polyspermy and poor cortical reaction were observed after insemination, even in oocytes in which CGs had completely moved to the cytoplasm immediately beneath the plasma membrane [4], oocytes do not always sufficiently mature, even if CGs are distributed i m m e d i a t e l y b e n e a t h t h e p l a s m a m e m b r a n e . Therefore, it is important to clarify the relationship between nuclear maturation and changes in CG distribution in porcine oocytes.In the present study, the state of nuclear maturation and the state of CG distribution were observed in porcine oocytes cultured for various periods in order to investigate the relationship between nuclear maturation and changes in CG distribution in oocytes. The state of

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Section: Discussionmentioning

confidence: 99%

Section: Cortical Granule Distribution Lectin Histochemistry Olomoumentioning

confidence: 99%

Section: Cortical Granule Distribution Lectin Histochemistry Olomoumentioning

confidence: 99%

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The Relationship between Nuclear Maturation and Cortical Granule Distribution in Cultured Porcine Oocytes

2002

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“…Among these, cortical granule migration from subcortical to cortical regions (Cran & Cheng 1985, Galeati et al 1991 in order to operate an efficient exocytosis (Ducibella et al 1990) at fertilization, the development of clusters of endoplasmic reticulum in the oocyte cortex (Mehlmann et al 1995), the increase of calcium in intracellular stores (Mehlmann & Kline 1994) to allow a prompt activation in response to fertilization (Carroll et al 1994 and the increase of cytosolic glutathione levels for the decondensation of penetrated sperm nucleus , Sutovsky & Schatten 1997, Zuelke et al 2003 are all essential steps for the acquisition of full developmental competence. More recently, it has been found that the parental chromatin remodelling that occurs before singamy appears to be the most sophisticated and complex task that the oocyte has to accomplish in order for embryo/fetal development to proceed regularly (McLay & Clarke 2003).…”

Section: Introductionmentioning

confidence: 99%

The capability of reprogramming the male chromatin after fertilization is dependent on the quality of oocyte maturation

Gioia¹,

Barboni²,

Turriani³

et al. 2005

Reproduction

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The present experiments compared the ability of pig oocytes matured either in vivo or in vitro to structurally reorganize the penetrated sperm chromatin into male pronucleus (PN) and to carry out, in parallel, the epigenetic processes of global chromatin methylation and acetylation, 12-14 h after in vitro fertilization (IVF). In addition, PN distribution of histone deacetylase (HDAC), a major enzyme interfacing DNA methylation and histone acetylation, was investigated. The ability of the oocyte to operate an efficient block to polyspermy was markedly affected by maturation. The monospermic fertilization rate was significantly higher for in vivo than for in vitro matured (IVM) oocytes (P < 0.01) which, furthermore, showed a reduced ability to transform the chromatin of penetrated sperm into male PN (P < 0.01). Indirect immunofluorescence analysis of global DNA methylation, histone acetylation and HDAC distribution (HDAC-1, -2 and -3), carried out in monospermic zygotes that reached the late PN stage, showed that IVM oocytes also had a reduced epigenetic competence. In fact, while in about 80% of in vivo matured and IVF oocytes the male PN underwent a process of active demethylation and showed a condition of histone H4 hyperacetylation, only 40% of IVM/IVF zygotes displayed a similar PN remodelling asymmetry. Oocytes that carried out the first part of maturation in vivo (up to germinal vesicle breakdown; GVBD) and then completed the process in vitro, displayed the same PN asymmetry as oocytes matured entirely in vivo. A crucial role of HDAC in the establishment of PN acetylation asymmetry seems to be confirmed by the use of HDAC inhibitors as well as by the abnormal distribution of the enzyme between the two PN in IVM zygotes. Collectively, these data demonstrated that some pig IVM oocytes fail to acquire full remodelling competence which is independent from their ooplasmic ability to morphologically reorganize the sperm nucleus into PN.

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“…The cortical granules become uniformely electron dense in the clusters and then are distributed to form an irregularly placed monolayer of a few nanometer distance from the cell membrane at about the time of ovulation (Cran and Cheng, 1985 Fifteen years ago we discovered the importance of granulosa cells in the cytoplasmic maturation of rabbit oocytes (Thibault andG6rard, 1970, 1973). When cumulus enclosed oocytes were matured outside their follicle, sperm nuclear decondensation did not follow the normal sequence and further development of the zygote was impaired.…”

mentioning

confidence: 99%