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Asymmetric cell division and axis formation in the embryo

2005; Linguagem: Inglês

10.1895/wormbook.1.30.1

1551-8507

Pierre Gönczy, Lesilee S. Rose,

Spaceflight effects on biology

asymmetric division.We first describe how the sperm-derived centrosome initiates movements of the cortical actomyosin network that result in the polarized distribution of PAR proteins.We then briefly discuss how components acting downstream of the PAR proteins mediate unequal segregation of cell fate determinants to the anterior blastomere AB and the posterior blastomere P 1 .We also review how a heterotrimeric G protein pathway generates cortically based pulling forces acting on astral microtubules, thus mediating centrosome and spindle positioning in response to AP polarity cues.In addition, we briefly highlight events involved in establishing the DV and LR axes.The DV axis is established at the four-cell stage, following specific cell-cell interactions that occur between P 2 and EMS, the two daughters of P 1 , as well as between P 2 and ABp, a daughter of AB.The LR axis is established shortly thereafter by the division pattern of ABa and ABp.We conclude by mentioning how findings made in early C. elegans embryos are relevant to understanding asymmetric cell division and pattern formation across metazoan evolution.