Not much is known about how organelles organize into patterns. In ciliates, the cortical pattern is propagated during “tandem duplication,” a cell division that remodels the parental cell into two daughter cells. A key step is the formation of the division boundary along the cell’s equator. In Tetrahymena thermophila, the cdaA alleles prevent the formation of the division boundary. We find that the CDAA gene encodes a cyclin E that accumulates in the posterior cell half, concurrently with accumulation of CdaI, a Hippo/Mst kinase, in the anterior cell half. The division boundary forms between the margins of expression of CdaI and CdaA, which exclude each other from their own cortical domains. The activities of CdaA and CdaI must be balanced to initiate the division boundary and to position it along the cell’s equator. CdaA and CdaI cooperate to position organelles near the new cell ends. Our data point to an intracellular positioning mechanism involving antagonistic Hippo signaling and cyclin E.

中文翻译：

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Hippo 信号传导和细胞周期蛋白 E 之间的相互拮抗作用驱动细胞内模式形成


人们对细胞器如何组织成模式知之甚少。在纤毛虫中，皮质模式在“串联复制”过程中传播，这是一种将亲本细胞重塑为两个子细胞的细胞分裂。关键步骤是沿着细胞赤道形成分裂边界。在嗜热四膜虫中，cdaA 等位基因阻止分裂边界的形成。我们发现 CDAA 基因编码的细胞周期蛋白 E 在后半部细胞中积累，同时 CdaI（一种 Hippo/Mst 激酶）在前半部细胞中积累。 CdaI 和 CdaA 的表达边缘之间形成划分边界，它们将彼此排除在自己的皮质域之外。 CdaA 和 CdaI 的活性必须平衡才能启动分裂边界并将其沿细胞赤道定位。 CdaA 和 CdaI 合作将细胞器定位在新细胞末端附近。我们的数据表明细胞内定位机制涉及拮抗性 Hippo 信号传导和细胞周期蛋白 E。