Alper S, Duncan L, Losick R
Department of Cellular and Developmental Biology, Harvard University, Cambridge, Massachusetts 02138.
Cell. 1994 Apr 22;77(2):195-205. doi: 10.1016/0092-8674(94)90312-3.
The sigma F factor establishes cell type-specific gene transcription during sporulation in B. subtilis. sigma F is negatively regulated by SpollAB, which forms complexes with sigma F or SpollAA. ATP and its nonhydrolyzable analogs stimulate the formation of the SpollAB.sigma F complex, whereas ADP stimulates the formation of the SpollAB.SpollAA complex. Which protein SpollAB associates with is determined by the concentrations of the two nucleotides, on which basis we propose a partner-switching model for the regulation of sigma F: [formula: see text] Consistent with this model, SpollAA reverses SpollAB-mediated inhibition of sigma F-directed transcription in a manner that depends on ADP. Cell-specific activation of sigma F could be due to an alteration in adenosine nucleotide levels in one cell of the sporangium.
在枯草芽孢杆菌的芽孢形成过程中，σF因子建立细胞类型特异性的基因转录。σF受到SpollAB的负调控，SpollAB与σF或SpollAA形成复合物。ATP及其不可水解的类似物刺激SpollAB.σF复合物的形成，而ADP刺激SpollAB.SpollAA复合物的形成。SpollAB与哪种蛋白质结合取决于两种核苷酸的浓度，基于此我们提出了一个用于调控σF的伴侣切换模型：[公式：见正文] 与该模型一致，SpollAA以依赖于ADP的方式逆转SpollAB介导的对σF指导转录的抑制。σF的细胞特异性激活可能是由于孢子囊的一个细胞中腺苷核苷酸水平的改变。
