نتایج جستجو برای: meiotic spindle

تعداد نتایج: 37218  

Journal: :The Journal of Cell Biology 1999
Linda M. Woods Craig A. Hodges Esther Baart Sean M. Baker Michael Liskay Patricia A. Hunt

In mouse oocytes, the first meiotic spindle is formed through the action of multiple microtubule organizing centers rather than a pair of centrosomes. Although the chromosomes are thought to play a major role in organizing the meiotic spindle, it remains unclear how a stable bipolar spindle is established. We have studied the formation of the first meiotic spindle in murine oocytes from mice ho...

2012
Xiao-Ling Xu Wei Ma Yu-Bo Zhu Chao Wang Bing-Yuan Wang Na An Lei An Yan Liu Zhong-Hong Wu Jian-Hui Tian

The microtubule-associated protein ASPM (abnormal spindle-like microcephaly-associated) plays an important role in spindle organization and cell division in mitosis and meiosis in lower animals, but its function in mouse oocyte meiosis has not been investigated. In this study, we characterized the localization and expression dynamics of ASPM during mouse oocyte meiotic maturation and analyzed t...

Ali Khodadadi, Ali Reza Eftekhari moghadam Ghasem Saki, Masoud Hemadi Zohre Mazaheri

Objective(s): Dehydroepiandrosterone (DHEA) has been reported to improve pregnancy chances in women with diminished ovarian reserve (DOR) and to reduce miscarriage rates by 50–80%. This study, therefore, assesses effects of DHEA on number of retrieved oocytes and meiotic spindles.Materials and Methods: A randomized, prospective, controlled study was conducted on eight groups, four groups of you...

Journal: :Reproductive biomedicine online 2009
Camila Madaschi Tsutomu Aoki Daniela Paes de Almeida Ferreira Braga Rita de Cássia Sávio Figueira Luciana Semião Francisco Assumpto Iaconelli Edson Borges

The meiotic spindle and the zona pellucida exhibit molecular order when imaged with polarized optics. This study aimed to investigate possible factors contributing to the zona pellucida birefringence score and meiotic spindle visualization, and to evaluate whether these structures may predict intracytoplasmic sperm injection outcomes. Oocytes were divided into groups according to zona pellucida...

Journal: :Human reproduction 2007
Hai-tao Zeng Zi Ren William S B Yeung Yi-min Shu Yan-wen Xu Guang-lun Zhuang Xiao-Yan Liang

BACKGROUND Birefrigent meiotic spindle in live human oocytes can be visualized by the PolScope. This study investigated the relationship between birefrigent meiotic spindle and cytoplasmic mitochondrial DNA (mtDNA) and ATP contents in in vitro matured human oocytes. METHODS Oocytes at germinal vesicle stage were collected and cultured for 24-48 h with or without the metabolic inhibitor, carbo...

Journal: :PLoS ONE 2009
Manqi Deng Juntao Gao Praveen Suraneni Rong Li

Kinetochores are considered to be the key structures that physically connect spindle microtubules to the chromosomes and play an important role in chromosome segregation during mitosis. Due to different mechanisms of spindle assembly between centrosome-containing mitotic cells and acentrosomal meiotic oocytes, it is unclear how a meiotic spindle generates the poleward forces to drive two rounds...

Journal: :The Journal of Cell Biology 2006
Karen McNally Anjon Audhya Karen Oegema Francis J. McNally

Accurate control of spindle length is a conserved feature of eukaryotic cell division. Lengthening of mitotic spindles contributes to chromosome segregation and cytokinesis during mitosis in animals and fungi. In contrast, spindle shortening may contribute to conservation of egg cytoplasm during female meiosis. Katanin is a microtubule-severing enzyme that is concentrated at mitotic and meiotic...

Journal: :Current Biology 2006
Jie Na Magdalena Zernicka-Goetz

The mature mammalian oocyte is highly polarized because asymmetrical spindle migration to the oocyte cortex ensures extrusion of small polar bodies in the two meiotic divisions, essential for generation of the large egg. Actin filaments, myosin motors, and formin-2, but not microtubules, are required for spindle migration. Here, we show that Cdc42, a key regulator of cytoskeleton and cell polar...

Journal: :The Journal of Cell Biology 1999
Stéphane Brunet Angélica Santa Maria Philippe Guillaud Denis Dujardin Jacek Z. Kubiak Bernard Maro

During meiosis, two successive divisions occur without any intermediate S phase to produce haploid gametes. The first meiotic division is unique in that homologous chromosomes are segregated while the cohesion between sister chromatids is maintained, resulting in a reductional division. Moreover, the duration of the first meiotic M phase is usually prolonged when compared with mitotic M phases ...

Journal: :The Journal of Cell Biology 1998
Lisa R. Matthews Philip Carter Danielle Thierry-Mieg Ken Kemphues

We describe the molecular characterization of zyg-9, a maternally acting gene essential for microtubule organization and function in early Caenorhabditis elegans embryos. Defects in zyg-9 mutants suggest that the zyg-9 product functions in the organization of the meiotic spindle and the formation of long microtubules. One-cell zyg-9 embryos exhibit both meiotic and mitotic spindle defects. Meio...

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