Development

Achieving Inequality

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Science  05 Jan 2001:
Vol. 291, Issue 5501, pp. 17
DOI: 10.1126/science.291.5501.17b

One of the ways that cellular diversity is generated is through asymmetric cell divisions, which produce two daughter cells of unequal size, protein content, or developmental potential. Prior to division, the cell fate determinants in the mother cell must become polarized and oriented properly with respect to the mitotic spindle.

In studies of the developing Drosophila nervous system, several groups report important progress in deciphering these mechanisms. Ohshiro et al., Peng et al., and Petronczki and Knoblich all identify several proteins that play critical roles in the localization of cell fate determinants to either the basal or apical cortex of neuroblasts in the central nervous system. These include the tumor suppressor proteins Lethal giant larvae and Lethal discs large, several myosins, and the DmPAR-6 protein. Meanwhile, work by Roegiers et al. illustrates that spindle orientation and determinant localization are also tightly coordinated in the sensory organ progenitor cells of the peripheral nervous system, and Bellaïche et al. show that the Frizzled protein is required for this coordination. — PAK'

Nature408, 593 (2000); Nature408, 596 (2000); Nature Cell Biol.3, 43; 58; 50 (2000).

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