Department of Biology and IGSP Center for Systems Biology, Duke University, Durham, North Carolina 27708, USA.
Nature. 2010 Jul 1;466(7302):128-32. doi: 10.1038/nature09143.
The development of multicellular organisms relies on the coordinated control of cell divisions leading to proper patterning and growth. The molecular mechanisms underlying pattern formation, particularly the regulation of formative cell divisions, remain poorly understood. In Arabidopsis, formative divisions generating the root ground tissue are controlled by SHORTROOT (SHR) and SCARECROW (SCR). Here we show, using cell-type-specific transcriptional effects of SHR and SCR combined with data from chromatin immunoprecipitation-based microarray experiments, that SHR regulates the spatiotemporal activation of specific genes involved in cell division. Coincident with the onset of a specific formative division, SHR and SCR directly activate a D-type cyclin; furthermore, altering the expression of this cyclin resulted in formative division defects. Our results indicate that proper pattern formation is achieved through transcriptional regulation of specific cell-cycle genes in a cell-type- and developmental-stage-specific context. Taken together, we provide evidence for a direct link between developmental regulators, specific components of the cell-cycle machinery and organ patterning.
多细胞生物的发育依赖于细胞分裂的协调控制，以实现正确的模式形成和生长。模式形成的分子机制，特别是成形细胞分裂的调控，仍然知之甚少。在拟南芥中，生成根基本组织的成形分裂受 SHORTROOT（SHR）和 SCARECROW（SCR）的控制。在这里，我们结合 SHR 和 SCR 的细胞类型特异性转录效应以及基于染色质免疫沉淀的微阵列实验数据，表明 SHR 调节特定细胞分裂相关基因的时空激活。与特定成形分裂的开始同时，SHR 和 SCR 直接激活 D 型细胞周期蛋白；此外，改变这种细胞周期蛋白的表达导致成形分裂缺陷。我们的结果表明，通过在细胞类型和发育阶段特异性的背景下对特定细胞周期基因进行转录调控，可以实现正确的模式形成。总的来说，我们提供了发育调节剂、细胞周期机制的特定成分和器官模式之间直接联系的证据。
