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Garc赤a-Blanco/Elsevier
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Yamada/Macmillan
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' G! @) h9 r$ i: y8 Q+ kDaniel Col車n-Ramos, Mariano A. Garc赤a-Blanco (Duke University, Durham, NC), and colleagues demonstrate in a recent article that Chlamydomonas nuclear architecture changes to accommodate cytoplasmic needs. p# C% C4 j+ q% H% `
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Chlamydomonas is a highly polarized cell that offers a unique system to study changes in nuclear shape. Loss of this algae's flagella (after certain chemical or mechanical stresses) causes the nucleus to adopt a pear-like shape and take an anterior position in the cell, nearer where the flagella once sat./ @: K9 L; D" b6 M
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Garc赤a-Blanco wondered whether sites of transcription of the ? tubulin gene, which is strongly up-regulated upon deflagellation, move closer to the flagella to expedite their rebuilding. Immunocytochemistry and electron microscopy revealed that the ? tubulin gene did not move from its posterior nuclear position. But the experiments did uncover an unexpected asymmetry of nuclear pore complex distribution.2 q3 \8 k& [" t/ ?" b, H8 Q
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Even in flagellated cells, the complexes were preferentially located at the posterior side of the nucleus, near a polysome-rich portion of the cytoplasm. Deflagellation further exaggerated the asymmetry. The changes correlated with accumulation of ? tubulin transcripts near the concentrated translation machinery. Says Garc赤a-Blanco, "what we don't know yet is what causes what." He hopes to find mutants that uncouple events following deflagellation to determine whether nuclear architecture directly targets mRNA cytoplasmic localization.
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Reference:
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/ B7 e! ~4 `8 W* xCol車n-Ramos, D., et al. 2003. Dev. Cell. 4:941–952.(NPCs (white) move to the posterior side ) |
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发表于 2009-3-6 00:37
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