Nuclear and spindle positioning during oocyte meiosis.
Summary of "Nuclear and spindle positioning during oocyte meiosis."
Female meiosis is unique in that an asymmetrically positioned meiotic spindle expels chromosomes into tiny, non-developing polar bodies. The extrusion of chromosomes into polar bodies is always mediated by meiotic spindles that are attached to the oocyte cortex by one pole. The asymmetric, cortical positioning of the oocyte meiotic spindle preserves the volume and contents of the oocyte. Recent work in C. elegans and mouse has provided mechanistic details of spindle positioning in oocytes.
Department of Molecular and Cellular Biology, University of California-Davis, Davis, CA 95616, United States.
This article was published in the following journal.
Name: Current opinion in cell biology
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20708397
- DOI: http://dx.doi.org/10.1016/j.ceb.2010.07.008
Medical and Biotech [MESH] Definitions
Protein kinase that drives both the mitotic and meiotic cycles in all eukaryotic organisms. In meiosis it induces immature oocytes to undergo meiotic maturation. In mitosis it has a role in the G2/M phase transition. Once activated by CYCLINS; MPF directly phosphorylates some of the proteins involved in nuclear envelope breakdown, chromosome condensation, spindle assembly, and the degradation of cyclins. The catalytic subunit of MPF is PROTEIN P34CDC2.
The phase of cell nucleus division following PROPHASE, when the breakdown of the NUCLEAR ENVELOPE occurs and the MITOTIC SPINDLE APPARATUS enters the nuclear region and attaches to the KINETOCHORES.
Crossing Over, Genetic
The reciprocal exchange of segments at corresponding positions along pairs of homologous CHROMOSOMES by symmetrical breakage and crosswise rejoining forming cross-over sites (HOLLIDAY JUNCTIONS) that are resolved during CHROMOSOME SEGREGATION. Crossing-over typically occurs during MEIOSIS but it may also occur in the absence of meiosis, for example, with bacterial chromosomes, organelle chromosomes, or somatic cell nuclear chromosomes.
An OOCYTE-containing structure in the cortex of the OVARY. The oocyte is enclosed by a layer of GRANULOSA CELLS providing a nourishing microenvironment (FOLLICULAR FLUID). The number and size of follicles vary depending on the age and reproductive state of the female. The growing follicles are divided into five stages: primary, secondary, tertiary, Graafian, and atretic. Follicular growth and steroidogenesis depend on the presence of GONADOTROPINS.
A lattice of fibrils which covers the entire inner surface of the nuclear envelope and interlinks nuclear pores (NUCLEAR PORE).
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