Cell Biology

Who Hid the Cyclin D2?

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Science  18 May 2012:
Vol. 336, Issue 6083, pp. 778-780
DOI: 10.1126/science.336.6083.778-c

During development of the cortex of the mammalian brain, radial glia divide asymmetrically to give rise to apical progenitor cells that continue to divide and cells that differentiate into neurons. Thus, the tissue supports the continued formation of neuronal structures while maintaining a pool of progenitors. Tsunekawa et al. report on a mechanism that influences the fate of the daughter cells. Radial glial cells have long thin apical and basal processes that extend from either end of the cell. mRNA encoding the cell cycle regulator cyclin D2 was preferentially localized and translated in the basal process because of a regulatory sequence in the 3' untranslated region of the mRNA. The daughter cell that inherited the basal process thus got most of the cyclin D2 and continued to proliferate. The other daughter cell, perhaps because of a prolonged cell cycle, or effects of other sequestered factors, underwent neuronal differentiation. A causal role of cyclin D2 was supported by experiments depleting or overexpressing the protein, which caused the accumulation of proliferating progenitor cells or increased neurogenesis, respectively.

EMBO J. 31, 1879 (2012).

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