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Garc赤a-Blanco/Elsevier) H" p6 S/ {+ T* L f
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Yamada/Macmillan( l F: g8 W( @1 J6 Y% f) j
& d+ Q# K6 f) K. @8 I+ y" A& e% Z) _Daniel 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.
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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.
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+ p3 i5 G: P! p) ?' jGarc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.6 Z" Z/ U" q8 m" I5 Q" ]5 a, W1 n
* K y- _' R4 r: V$ F: G! q. sEven 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.. f4 r: f* f/ F/ \( V
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Col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
发表于 2015-5-28 21:45
