Spatial control of cell differentiation in Myxococcus xanthus
Spatial control of cell differentiation in Myxococcus xanthus
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DOI：
10.1073/pnas.97.16.9098
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发表时间：
2000-08-01
影响因子：
11.1
通讯作者：
Garza, A
中科院分区：
文献类型：
--
作者：
Julien, B;Kaiser, AD;Garza, A
黄色粘球菌发育特定物种的多细胞子实体。从一团均匀的细胞开始，一些细胞进入新生的子实体聚合体，而另一些细胞则留在外面。子实体内的细胞由杆状分化成球形的耐热孢子，而聚合体外的细胞称为外围细胞，保持杆状。早期发育调节基因在外周细胞和子实体细胞中表达。相比之下，发育迟缓的基因只在初生子实体内的细胞中表达。数据显示，外周细胞开始发育，但不能表达晚于发育开始后约6小时启动的基因。所有表达局限于子实体的基因都直接或间接依赖于C-信号，而在外周杆状细胞和子实体细胞中同等表达的基因则不依赖于C-信号。其中一个依赖于C信号的空间模式操纵子被称为dev，dev操纵子参与了孢子形成过程。有人认为，某些基因的表达，包括dev操纵子的基因，仅限于初生子实体，因为子实体细胞参与高水平的C信号。与子实体细胞相比，外周细胞产生的C-信号较少，因为它们的空间排列不同，密度也较低。因此，外周细胞不能表达孢子分化所需的晚期基因。
Myxococcus xanthus develops species-specific multicellular fruiting bodies. Starting from a uniform mat of cells, some cells enter into nascent fruiting body aggregates, whereas other cells remain outside. The cells within the fruiting body differentiate from rods into spherical, heat-resistant spores, whereas the cells outside the aggregates, called peripheral cells, remain rod-shaped. Early developmentally regulated genes are expressed in peripheral cells as well as by cells in the fruiting bodies. By contrast, late developmental genes are only expressed by cells within the nascent fruiting bodies. The data show that peripheral cells begin to develop, but are unable to express genes that are switched on later than about 6 h after the start of development. All of the genes whose expression is limited to the fruiting body are dependent on C-signaling either directly or indirectly, whereas the genes that are equally expressed in peripheral rods and in fruiting body cells are not. One of the C-signal-dependent and spatially patterned operons is called dev, and the dev operon has been implicated in the process of sporulation. It is proposed that expression of certain genes, including those of the dev operon, is limited to the nascent fruiting body because fruiting body cells engage in a high level of C-signaling. Peripheral cells do less C-signaling than fruiting body cells, because they have a different spatial arrangement and are at lower density. As a consequence, peripheral cells fail to express the late genes necessary for spore differentiation.