Providencia stuartii genes activated by cell-to-cell signaling and identification of a gene required for production or activity of an extracellular factor
Providencia stuartii genes activated by cell-to-cell signaling and identification of a gene required for production or activity of an extracellular factor
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DOI：
10.1128/jb.181.23.7185-7191.1999
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发表时间：
1999-12-01
影响因子：
3.2
通讯作者：
Siddiqui, S
中科院分区：
文献类型：
--
作者：
Rather, PN;Ding, XD;Siddiqui, S
通过利用报告转座子，已经鉴定了5个由自身产生的胞外信号积累激活的普罗维登西亚·斯图阿蒂基因。这些基因被指定为条件培养液激活的CMA。在富营养液中生长的固定相培养中的条件培养液的存在导致细胞中每个基因在对数早期过早激活，激活值在6-26倍之间。从M9盐培养基制备条件培养基，并用凝胶过滤层析进行分级，得到包涵体内的组分，从而激活了三个CMA融合。此外，根据报告融合的不同，在不同的级分中发现了峰值活性。部分纯化的因子以剂量依赖的方式激活。对激活CMA融合的因素进行了表征，结果表明它们对热、碱和酸都是稳定的。此外，对于每个CMA融合，因子活性，VAS不是通过添加高丝氨酸内酯、同型半胱氨酸硫内酯、丙酮酸、酪氨酸或α-酮戊二酸而复制的。三个CMA基因的同源性已被确定，并揭示了它们在氨基酸生物合成和营养输入中的生理作用。为了开始解决产生或响应细胞外因子的途径，我们已经确定了激活四个CMA融合所需的一个基因位点AARA。AARA产物是细胞外上清液中的因子活性所必需的，这表明它可能在生物合成或输出中发挥作用。
By utilizing reporter transposons, five Providencia stuartii genes that are activated by the accumulation of self-produced extracellular signals have been identified. These genes have been designated cma for conditioned medium activated. The presence of conditioned medium from stationary-phase cultures grown in rich media resulted in the premature activation of each gene in cells at early log phase, with activation values ranging from 6- to 26-fold. Preparation of conditioned medium from an M9 salts medium and fractionation by gel filtration chromatography resulted in fractions within the included volume which activated three of the cma fusions. In addition, depending on the reporter fusion, peak activity was found in different fractions. The partially purified factors activated in a dose-dependent manner. Characterization of the factors activating the cma fusions indicated that they were stable to heat, alkali, and acid. Furthermore, for each cma fusion, factor activity,vas not reproduced by the addition of homoserine lactone, homocysteine thiolactone, pyruvate, Casamino Acids, or a-ketoglutarate. The identities of three cma genes have been determined and revealed physiological roles in amino acid biosynthesis and nutrient import. To begin to address the pathways for production of or response to the extracellular factors, we have identified a locus, aarA, that is required for the activation of four cma fusions. The AarA product was required for factor activity in extracellular supernatants, indicating a possible role in biosynthesis or export.