极化中的奇点:重新连接酵母细胞以制造两个芽
Audrey S Howell1, Natasha S Savage, Sam A Johnson
1Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
Cell
|November 17, 2009
概括
酵母细胞通过Cdc42反循环确保单个芽. 重新连接这个循环破坏了这种"奇点",导致多个芽,突出了Cdc42集群之间快速竞争对于适当的细胞分裂的重要性.
科学领域:
- 细胞生物学 细胞生物学
- 分子生物学分子生物学
- 生物物理学的生物物理.
背景情况:
- 发芽的酵母细胞必须在单一位置建立极性,以便进行适当的分裂.
- 该Rho GTPase Cdc42通过正反循环在极化部位集中,这对于极性建立至关重要.
- 确保只形成一个芽 (奇点) 的机制尚未完全理解.
研究的目的:
- 调查酵母中芽部选择的奇异性是否与特定的Cdc42正反循环密切相关.
- 为了确定是否有替代的正反机制可以维持或破坏芽部位的奇点.
- 探索Cdc42集群之间的竞争在强制形成单个芽的作用.
主要方法:
- 在芽酵母中禁用内源Cdc42放大机制.
- 合成重新连接酵母细胞,以利用不同的Cdc42度的正反循环.
- 在正常细胞和重新连接的细胞中观察和量化芽形成和Cdc42集群动态.
- 使用数学建模来模拟集群竞争及其对奇点的影响.
主要成果:
- 重新连接的细胞表现出奇点的丧失,偶尔会形成两个芽.
- 即使在形成单个芽的细胞中,也观察到多个Cdc42集群的初始形成,随后有一种Cdc42集群的统治地位.
- 数学建模表明,Cdc42星团之间的竞争会随着时间的推移促进奇点.
- 在重新连接的细胞中,Cdc42集群之间的竞争较慢,有时在芽之前无法建立单一的主导集群.
- 正常细胞中的竞争减缓也导致偶尔的双芽形成.
结论:
- 特定的Cdc42正反循环对于强制执行酵母中的芽部位奇点至关重要.
- 新兴Cdc42集群之间的快速竞争强化了奇点.
- 替代反机制,如果不与快速竞争相结合,可能导致奇点的失败和多个芽事件.
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