LET-99 inhibits lateral posterior pulling forces during asymmetric spindle elongation in C. elegans embryos.
LET-99 inhibits lateral posterior pulling forces during asymmetric spindle elongation in C. elegans embryos.
复制标题
LET-99 抑制线虫胚胎中纺锤体不对称伸长过程中的横向后拉力。
DOI：
10.1083/jcb.201001115
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Rose,LesileeS
中科院分区：
文献类型：
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作者：
Krueger,LoriE;Wu,Jui-Ching;Tsou,Meng-FuBryan;Rose,LesileeS
在许多系统中，皮质对星形微管的牵拉定位有丝分裂纺锤体以响应PAR极性线索和G蛋白信号。在秀丽隐杆线虫单细胞胚胎中，后纺锤体移位依赖于Gα及其调节因子GPR-1/2和LIN-5。GPR-1/2和LIN-5是皮质拉力所必需的，并在后皮质富集，这表明与前极相比，更高的力作用于后梭极。然而，皮质力的精确分布以及它们如何被调节仍有待确定。使用纺锤体切断，单中心体测定，和中心体碎片，我们表明，前部和后部皮质产生更多的拉力比侧后部区域。侧向抑制依赖于LET-99，其抑制GPR-1/2定位以产生双极GPR-1/2模式。因此，皮质力的领域不是两个，而是三个。我们建议，横向力的衰减防止适得其反的拉动，导致更高的净力朝向后方，有助于主轴伸长和位移。
Cortical pulling on astral microtubules positions the mitotic spindle in response to PAR polarity cues and G protein signaling in many systems. InCaenorhabditis eleganssingle-cell embryos, posterior spindle displacement depends on Gα and its regulators GPR-1/2 and LIN-5. GPR-1/2 and LIN-5 are necessary for cortical pulling forces and become enriched at the posterior cortex, which suggests that higher forces act on the posterior spindle pole compared with the anterior pole. However, the precise distribution of cortical forces and how they are regulated remains to be determined. Using spindle severing, single centrosome assays, and centrosome fragmentation, we show that both the anterior and posterior cortices generate more pulling force than the lateral–posterior region. Lateral inhibition depends on LET-99, which inhibits GPR-1/2 localization to produce a bipolar GPR-1/2 pattern. Thus, rather than two domains of cortical force, there are three. We propose that the attenuation of lateral forces prevents counterproductive pulling, resulting in a higher net force toward the posterior that contributes to spindle elongation and displacement.