RNA POLYMERASE AND BACTERIAL DIFFERENTIATION

本项目的目的是了解枯草芽孢杆菌孢子形成过程中基因转录的控制，以及孢子形成基因的表达如何指导形态发生过程，并与形态发生过程保持一致。 孢子形成涉及极隔膜的形成，极隔膜将发育中的细胞分成前孢子和母细胞。 最初，两个细胞并排放置，但后来前孢子被母细胞吞噬。 有证据表明，极隔是一个细胞器，是密切参与建立细胞特异性基因转录。 差异转录最初由前孢子中的转录因子sigmaF和母细胞中的转录因子sigmaE的作用控制。 吞噬后，sigmaF和sigmaE分别被sigmaG和sigmaK取代。 将进行实验，以了解隔膜形成如何从中间切换到极性位置。 已知将sigmaF的激活与极隔联系起来的途径。 将进行实验，以了解隔膜相关的磷酸酶和抗sigmaF因子的蛋白水解在sigmaF激活中的作用。sigmaE因子来源于pro-sigmaE，其在通过蛋白水解加工进行活化之前与隔膜缔合。 将进行实验以了解隔膜相关蛋白在限制sigmaE进入母细胞中的作用。 sigmaK因子来源于pro-sigmaK，其激活受与sigmaG作用偶联的细胞间途径控制。 将进行实验以确定该途径的组分如何响应来自前孢子的信号介导pro-sigmaK加工。 孢子形成涉及在sigmaE控制下产生的形态发生蛋白在前孢子周围的组装。 将进行实验以了解这种蛋白质的定位及其在招募外壳蛋白和触发皮质合成中的作用。 这些目标解决了分化和形态发生的基本问题，这些问题对于许多种类的发育系统是共同的，包括高等生物中正常和异常发育的复杂系统。

The objectives of this project are to understand the control of gene transcription during sporulation in Bacillus subtilis and how the expression of sporulation genes both directs, and is kept in register with, the course of morphogenesis. Sporulation involves the formation of a polar septum, which divides the developing cell into a forespore and a mother cell. Initially, the two cells lie side-by-side but later the forespore is engulfed by the mother cell. Evidence indicates that the polar septum is an organelle that is intimately involved in the establishment of cell-specific gene transcription. Differential transcription is governed initially by the action of transcription factor sigmaF in the forespore and sigmaE in the mother cell. After engulfment, sigmaF and sigmaE are replaced by sigmaG and sigmaK, respectively. Experiments will be carried out to understand how septum formation switches from a medial to a polar position. A pathway is known that links the activation of sigmaF to the polar septum. Experiments will be carried out to understand the roles of a septum-associated phosphatase and the proteolysis of an antisigma factor in the activation of sigmaF. The sigmaE factor is derived from pro-sigmaE, which associates with the septum prior to undergoing activation by proteolytic processing. Experiments will be carried out to understand the role of a septum-associated protein in restricting sigmaE to the mother cell. The sigmaK factor is derived from pro-sigmaK, whose activation is governed by an intercellular pathway that is coupled to the action of sigmaG. Experiments will be carried out to determine how the components of the pathway mediate pro-sigmaK processing in response to a signal from the forespore. Spore formation involves the assembly around the forespore of a morphogenetic protein that is produced under the control of sigmaE. Experiments will be carried out to understand the localization of this protein and its role in recruiting coat proteins and triggering cortex synthesis. These objectives address basic questions of differentiation and morphogenesis that are common to developing systems of many kinds, including complex systems of normal and abnormal development in higher organisms.