MULTISENSORY ACTIVATION OF THE PHOSPHORELAY INITIATING SPORULATION IN BACILLUS-SUBTILIS - IDENTIFICATION AND SEQUENCE OF THE PROTEIN-KINASE OF THE ALTERNATE PATHWAY
MULTISENSORY ACTIVATION OF THE PHOSPHORELAY INITIATING SPORULATION IN BACILLUS-SUBTILIS - IDENTIFICATION AND SEQUENCE OF THE PROTEIN-KINASE OF THE ALTERNATE PATHWAY
复制标题
DOI：
10.1111/j.1365-2958.1993.tb01204.x
复制
发表时间：
1993-04-01
影响因子：
3.6
通讯作者：
HOCH, JA
中科院分区：
文献类型：
--
作者：
TRACH, KA;HOCH, JA
磷接力是一种信号转导系统，可以识别和整合环境信号，从而启动孢子形成。磷酸化接力的主要信号输入是atp依赖性激酶KinA，它负责磷酸化Spo0F蛋白。然而，缺乏KinA的突变体仍然产生孢子，这表明其他激酶可以发挥其作用。为了鉴定这些激酶，使用专为这类激酶的共同区域设计的退化寡核苷酸探针，通过杂交分离出激酶的基因。第二个激酶KinB的基因被分离出来，当在kinA背景下失活时，该基因具有产孢阴性表型。对kinB基因座进行了测序，发现它是一个由kinB基因和另一个基因kapB组成的小操纵子，由单个sigma(a)依赖性启动子转录而成。在一个kinA菌株中，kinB或kapB的失活导致严重的孢子形成缺陷。kinB基因编码一个47774 M(r)蛋白，该蛋白的羧基一半与KinA的相同结构域高度同源。KinB的氨基末端结构域是疏水的，具有六个可识别的跨膜区域。kapB基因编码了一个中等电荷，可能是可溶的，14 668 M(r)的蛋白质，与任何已知的蛋白质没有同源性。遗传证据表明，KapB是KinB功能或其表达所必需的。虽然双突变体kinAkinB不能产孢并呈现0期表型，但在这些菌株中，SpoA类似于P依赖的abrB基因调控是正常的，这表明低水平的SpoA类似于P积累，即使在缺乏这两种激酶的情况下。这种积累依赖于功能性spo0F和spo0B基因，其来源尚不清楚。在实验室条件下，KinA和KinB途径是唯一能够产生足够Spo0A的途径，Spo0A类似于P，允许孢子形成和完成。
The phosphorelay is the signal-transduction system recognizing and integrating environmental signals to initiate sporulation. The major signal input to the phosphorelay is an ATP-dependent kinase, KinA, responsible for phosphorylating the Spo0F protein. Mutants lacking KinA, however, still sporulate, suggesting that other kinases can fulfil its role. In order to identify these kinases, genes for kinases were isolated by hybridization using a degenerate oligonucleotide probe designed for common regions of this class of kinases. A gene for a second kinase, KinB, was isolated which gave a sporulation negative phenotype when inactivated in a kinA background. The kinB locus was sequenced and found to be a small operon consisting of the kinB gene and another gene, kapB, transcribed from a single sigma(A)-dependent promoter. Inactivation of either kinB or kapB in a kinA strain led to severe sporulation deficiency. The kinB gene coded for a 47774 M(r) protein with the carboxyl half of this protein highly homologous to the same domain of KinA. The amino-terminal domain of KinB was hydrophobic with six recognizable membrane-spanning regions. The kapB gene coded for a moderately charged, probably soluble, protein of 14 668 M(r) with no homology to any known protein. Genetic evidence suggests that KapB is required either for the function of KinB or for its expression. Although double mutants kinAkinB cannot sporulate and assume a stage 0 phenotype, the SpoA is similar to P-dependent regulation of the abrB gene is normal in these strains, suggesting that low levels of SpoA is similar to P accumulate even in the absence of both kinases. This accumulation is dependent on functional spo0F and spo0B genes and its source is unknown. The KinA and KinB pathways are the only pathways capable of producing sufficient Spo0A is similar to P to allow initiation and completion of sporulation under laboratory conditions.