Rousselet A, Euteneuer U, Bordes N, Ruiz T, Hui Bon Hua G, Bornens M
Laboratoire du cycle cellulaire et de la motilité, UMR144-CNRS, Institut Curie, Paris, France.
Cell Motil Cytoskeleton. 2001 Apr;48(4):262-76. doi: 10.1002/cm.1014.
In an attempt to better understand the role of centrioles in vertebrate centrosomes, hydrostatic pressure was applied to isolated centrosomes as a means to disassemble centriole microtubules. Treatments of the centrosomes were monitored by analyzing their protein composition, ultrastructure, their ability to nucleate microtubules from pure tubulin, and their capability to induce parthenogenetic development of Xenopus eggs. Moderate hydrostatic pressure (95 MPa) already affected the organization of centriole microtubules in isolated centrosomes, and also impaired microtubule nucleation. At higher pressure, the protein composition of the peri-centriolar matrix (PCM) was also altered and the capacity to nucleate microtubules severely impaired. Incubation of the treated centrosomes in Xenopus egg extract could restore their capacity to nucleate microtubules after treatment at 95 MPa, but not after higher pressure treatment. However, the centriole structure was in no case restored. It is noteworthy that centrosomes treated with mild pressure did not allow parthenogenetic development after injection into Xenopus eggs, even if they had recovered their capacity to nucleate microtubules. This suggested that, in agreement with previous results, centrosomes in which centriole architecture is impaired, could not direct the biogenesis of new centrioles in Xenopus eggs. Centriole structure could also be affected by applying mild hydrostatic pressure directly to living cells. Comparison of the effect of hydrostatic pressure on cells at the G1/S border or on the corresponding cytoplasts suggests that pro-centrioles are very sensitive to pressure. However, cells can regrow a centriole after pressure-induced disassembly. In that case, centrosomes eventually recover an apparently normal duplication cycle although with some delay.
为了更好地理解中心粒在脊椎动物中心体中的作用，对分离出的中心体施加静水压力，作为拆解中心粒微管的一种手段。通过分析中心体的蛋白质组成、超微结构、从纯微管蛋白中形成微管的能力以及诱导非洲爪蟾卵孤雌生殖发育的能力，来监测对中心体的处理。适度的静水压力（95兆帕）已经影响了分离出的中心体中中心粒微管的组织，也损害了微管的形成。在更高的压力下，中心粒周围基质（PCM）的蛋白质组成也发生了改变，形成微管的能力严重受损。将处理过的中心体在非洲爪蟾卵提取物中孵育，可以恢复其在95兆帕处理后的微管形成能力，但在更高压力处理后则不能。然而，中心粒结构在任何情况下都没有恢复。值得注意的是，即使轻度压力处理过的中心体已经恢复了形成微管的能力，将其注射到非洲爪蟾卵中后也不能使其孤雌生殖发育。这表明，与先前的结果一致，中心粒结构受损的中心体不能指导非洲爪蟾卵中新中心粒的生物发生。直接对活细胞施加轻度静水压力也会影响中心粒结构。比较静水压力对处于G1/S边界的细胞或相应细胞质体的影响表明，原中心粒对压力非常敏感。然而，细胞在压力诱导拆解后可以重新长出一个中心粒。在这种情况下，中心体最终会恢复一个明显正常的复制周期，尽管会有一些延迟。
