The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Guoliang Xia - One of the best experts on this subject based on the ideXlab platform.
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cyclic amp in oocytes controls meiotic prophase i and primordial folliculogenesis in the perinatal mouse ovary
Development, 2015Co-Authors: Yijing Wang, Lizhao Feng, Zhengpin Wang, Chao Wang, Zhen Teng, Wanbao Niu, Kun Huang, Xi Xiang, Hua Zhang, Guoliang XiaAbstract:In mammalian ovaries, a fixed population of primordial follicles forms during the perinatal stage and the oocytes contained within are arrested at the Dictyate stage of meiotic prophase I. In the current study, we provide evidence that the level of cyclic AMP (cAMP) in oocytes regulates oocyte meiotic prophase I and primordial folliculogenesis in the perinatal mouse ovary. Our results show that the early meiotic development of oocytes is closely correlated with increased levels of intra-oocyte cAMP. Inhibiting cAMP synthesis in fetal ovaries delayed oocyte meiotic progression and inhibited the disassembly and degradation of synaptonemal complex protein 1. In addition, inhibiting cAMP synthesis in in vitro cultured fetal ovaries prevented primordial follicle formation. Finally, using an in situ oocyte chromosome analysis approach, we found that the Dictyate arrest of oocytes is essential for primordial follicle formation under physiological conditions. Taken together, these results suggest a role for cAMP in early meiotic development and primordial follicle formation in the mouse ovary.
José L. Barbero - One of the best experts on this subject based on the ideXlab platform.
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Cohesin component dynamics during meiotic prophase I in mammalian oocytes
Chromosome Research, 2004Co-Authors: Ignacio Prieto, Nieves Pezzi, Leonor Kremer, Jose Marı́a Buesa, Alicia Martínez, Charles Tease, Sagrario Ortega, Carlos Martínez-a, Maj A. Hultén, José L. BarberoAbstract:Cohesins are chromosomal proteins that form complexes involved in the maintenance of sister chromatid cohesion during division of somatic and germ cells. Three meiosis-specific cohesin subunits have been reported in mammals, REC8, STAG3 and SMC1β; their expression in mouse spermatocytes has also been described. Here we studied the localization of different meiotic and mitotic cohesin components during prophase I in human and murine female germ cells. In normal and atretic human fetal oocytes, from leptotene to diplotene stages, REC8 and STAG3 colocalize in fibers. In murine oocytes, SMC1β, SMC3 and STAG3 are localized along fibers that correspond first to the chromosome axis and then to the synaptonemal complex in pachytene. Mitotic cohesin subunit RAD21 is also found in fibers that decorate the SC during prophase I in mouse oocytes, suggesting a role for this cohesin in mammalian sister chromatid cohesion in female meiosis. We observed that, unlike human oocytes, murine synaptonemal complex protein SYCP3 localizes to nucleoli throughout prophase I stages, and centromeres cluster in discrete locations from leptotene to Dictyate. At difference from meiosis in male mice, the cohesin axis is progressively lost during the first week after birth in females with a parallel destruction of the axial elements at Dictyate arrest, demonstrating sexual dimorphism in sister chromatid cohesion in meiosis.
Ian R Adams - One of the best experts on this subject based on the ideXlab platform.
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oocyte development meiosis and aneuploidy
Seminars in Cell & Developmental Biology, 2015Co-Authors: Marie Maclennan, James H Crichton, Christopher J Playfoot, Ian R AdamsAbstract:Meiosis is one of the defining events in gametogenesis. Male and female germ cells both undergo one round of meiotic cell division during their development in order to reduce the ploidy of the gametes, and thereby maintain the ploidy of the species after fertilisation. However, there are some aspects of meiosis in the female germline, such as the prolonged arrest in Dictyate, that appear to predispose oocytes to missegregate their chromosomes and transmit aneuploidies to the next generation. These maternally-derived aneuploidies are particularly problematic in humans where they are major contributors to miscarriage, age-related infertility, and the high incidence of Down's syndrome in human conceptions. This review will discuss how events that occur in foetal oocyte development and during the oocytes’ prolonged Dictyate arrest can influence meiotic chromosome segregation and the incidence of aneuploidy in adult oocytes.
Yijing Wang - One of the best experts on this subject based on the ideXlab platform.
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cyclic amp in oocytes controls meiotic prophase i and primordial folliculogenesis in the perinatal mouse ovary
Development, 2015Co-Authors: Yijing Wang, Lizhao Feng, Zhengpin Wang, Chao Wang, Zhen Teng, Wanbao Niu, Kun Huang, Xi Xiang, Hua Zhang, Guoliang XiaAbstract:In mammalian ovaries, a fixed population of primordial follicles forms during the perinatal stage and the oocytes contained within are arrested at the Dictyate stage of meiotic prophase I. In the current study, we provide evidence that the level of cyclic AMP (cAMP) in oocytes regulates oocyte meiotic prophase I and primordial folliculogenesis in the perinatal mouse ovary. Our results show that the early meiotic development of oocytes is closely correlated with increased levels of intra-oocyte cAMP. Inhibiting cAMP synthesis in fetal ovaries delayed oocyte meiotic progression and inhibited the disassembly and degradation of synaptonemal complex protein 1. In addition, inhibiting cAMP synthesis in in vitro cultured fetal ovaries prevented primordial follicle formation. Finally, using an in situ oocyte chromosome analysis approach, we found that the Dictyate arrest of oocytes is essential for primordial follicle formation under physiological conditions. Taken together, these results suggest a role for cAMP in early meiotic development and primordial follicle formation in the mouse ovary.
Ignacio Prieto - One of the best experts on this subject based on the ideXlab platform.
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Cohesin component dynamics during meiotic prophase I in mammalian oocytes
Chromosome Research, 2004Co-Authors: Ignacio Prieto, Nieves Pezzi, Leonor Kremer, Jose Marı́a Buesa, Alicia Martínez, Charles Tease, Sagrario Ortega, Carlos Martínez-a, Maj A. Hultén, José L. BarberoAbstract:Cohesins are chromosomal proteins that form complexes involved in the maintenance of sister chromatid cohesion during division of somatic and germ cells. Three meiosis-specific cohesin subunits have been reported in mammals, REC8, STAG3 and SMC1β; their expression in mouse spermatocytes has also been described. Here we studied the localization of different meiotic and mitotic cohesin components during prophase I in human and murine female germ cells. In normal and atretic human fetal oocytes, from leptotene to diplotene stages, REC8 and STAG3 colocalize in fibers. In murine oocytes, SMC1β, SMC3 and STAG3 are localized along fibers that correspond first to the chromosome axis and then to the synaptonemal complex in pachytene. Mitotic cohesin subunit RAD21 is also found in fibers that decorate the SC during prophase I in mouse oocytes, suggesting a role for this cohesin in mammalian sister chromatid cohesion in female meiosis. We observed that, unlike human oocytes, murine synaptonemal complex protein SYCP3 localizes to nucleoli throughout prophase I stages, and centromeres cluster in discrete locations from leptotene to Dictyate. At difference from meiosis in male mice, the cohesin axis is progressively lost during the first week after birth in females with a parallel destruction of the axial elements at Dictyate arrest, demonstrating sexual dimorphism in sister chromatid cohesion in meiosis.