Rong Li Lab probes mechanism of asymmetry in meiotic cell division

October 08, 2008

The Stowers Institute's Rong Li Lab has characterized a mechanism that allows for asymmetrical cell division during meiosis in oocytes. By tracking chromosome movement in live mouse oocytes, the team discovered that chromosomes can recruit to their vicinity a protein called formin-2. This protein allows the oocyte to retain the majority of the cytoplasm - a requirement for embryonic development after fertilization - while the other daughter cell (called a polar body) resulting from the asymmetric division gets only a minimal amount and subsequently dies.

The work was published this week in the advance online publication of Nature Cell Biology.

Formin-2 is an actin-nucleating protein that can promote the formation of actin filaments around the chromosomes. Actin filaments undergo dynamic elongation and shortening and, in the process, push the chromosomes towards the outer edge of the oocyte. After the chromosomes reach the periphery, the actin filaments orient the cell division plane so that most of the cytoplasm required to sustain the earliest stages of development stays with the daughter cell that retains the identy of the oocyte.

"This work revealed the general mechanism by which the actin cytoskeleton drives chromosome movement in mammalian meiotic oocytes," said Hongbin Li, Ph.D., Senior Research Associate and lead author on the publication. "Our findings will enable us to carry out even more detailed dissection of the molecular components and mechanisms."

"Infertility and birth defects are often related to problems during oocyte meiotic cell divisions," said Rong Li, Ph.D., Investigator and senior author on the paper. "Failure in the chromosome movement will lead to failed oocyte maturation and infertility. These findings provide an important step toward a better understanding of the process of meiotic divisions and how actin generates the force to power intra-cellular movements."

Stowers Institute for Medical Research

Atlas of Oocytes, Zygotes and Embryos in Reproductive Medicine
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The assessment and selection of oocytes and embryos is fundamental to the live birth rate data of all IVF units, the parameter that is used to gauge a clinic's success and credibility. This new atlas contains over 1000 high-quality images of oocytes, zygotes and embryos, presented with accompanying data on indications for treatment, stimulation type and duration, as well as short medical histories of each couple and final outcome of treatment. All images in the book can be downloaded from the accompanying CD-ROM. Structured on a patient-by-patient basis, the atlas describes 100 clinically documented case studies that follow the evolution of oocytes and zygotes between day two and day five. Pronuclear morphology and synchrony as well as embryo morphology are reported and described for each...

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Since the first successful transfer of an in vitro fertilised human egg in 1976, modern endocrinology, genetics, and assisted reproductive technologies have opened new frontiers of research with the aim to treat infertile women. In this workshop we set out to promote an interdisciplinary discussion between experts from various fields of basic, company-based and clinical research related to folliculogenesis and oocyte development. The aim of this workshop was to present, discuss and assess novel approaches in mammalian folliculogenesis and oocyte development that may have an impact on fertility/ infertility in the near or distant future. Key issues were the understanding of new modulators of folliculogenesis and regulators of cytoplasmic as well as meiotic oocyte maturation, modern...

Oocyte structure and ultrastructure in the Mexican silverside fish Chirostoma humboldtianum (Atheriniformes: Atherinopsidae).: An article from: Revista de Biologîa Tropical
by Rodolfo Cârdenas (Author), Mônica Châvez (Author), Josê Luis Gonzâlez (Author), Patricia Aley (Author), Jesûs Espinosa (Author), Luis Felipe Jimênez-Garcîa (Author)

This digital document is an article from Revista de Biologîa Tropical, published by Universidad de Costa Rica on December 1, 2008. The length of the article is 3703 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available immediately after purchase. You can view it with any web browser.

From the author: Key words: Chirostoma, ovary, ultrastructure, oocyte, teleost.

Citation Details
Title: Oocyte structure and ultrastructure in the Mexican silverside fish Chirostoma humboldtianum (Atheriniformes: Atherinopsidae).
Author: Rodolfo Cârdenas
Publication: Revista de Biologîa Tropical (Magazine/Journal)
Date: December 1, 2008
Publisher: Universidad de Costa Rica
Volume: 56 Issue: 4 ...

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