权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

A novel signal transduction system involved in osmotic adjustment in Myxococcus xanthus.

一种参与黄色粘球菌渗透压调节的新型信号转导系统。

基本信息

批准号：
14560072
负责人：
KIMURA Yoshio
金额：
$ 2.3万
依托单位：
Kagawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

Two adenylyl cyclase genes (cyaA and cyaB) were isolated from Myxococcus xanthus. The predicted cyaA and cyaB gene products had structural similarity to the receptor-type adenylyl cyclases that are composed of an amino-terminal sensor domain and a carboxy-terminal catalytic domain of adenylyl cyclase. A cyaA mutant, placed under condition of high-ionic (NaCl) or high-nonionic (sucrose) osmostress exhibited a marked reduction in spore formation and spore germination. In vegetative cells, cyaA mutant responded normally to osmotic stress. On the other hand, disruption of cyaB generates a mutant that showed growth retardation at high-ionic (NaCl) or high-nonionic (sucrose) osmolarity. Under nonionic osmostress, the cyaB mutant exhibited reduced spore germination, however, the germination rate of the cyaB mutant was significantly higher than that of the cyaA mutant. These results suggested that M. xanthus CyaA and CyaB function as osmosensors mainly during development and spore germination, … More and throughout the life cycle of M. xanthus including the vegetative stage, respectively.Next, we isolated a clone from a M. xanthus genomic DNA library using oligonucleotide probes designed based on the conserved cAMP-binding domains of the cAMP-dependent protein kinase (PKA) regulatory subunits. The clone contained an open-reading frame, cbpB, encoding a hydrophilic protein with two cAMP-binding domains. The CbpB exhibited partial primary structural similarity to PKA regulatory subunits. cbpB mutant showed normal growth, development and spore germination. However, the cbpB mutant cultured under high- or low-temperature conditions exhibited a marked reduction in growth. cbpB mutant cells were also more sensitive to osmotic stress than wild-type cells. The phenotype of cbpB mutant was similar to those of PKA regulatory subunit mutants of some eukaryotic microorganisms. These results suggest that the cAMP-mediated signal transduction pathway plays an important role in osmotic and temperature adaptation in M. xanthus. The cAMP-mediated signal transduction pathway is not reported in bacteria. Less

从黄色粘球菌（Myxococcus xanthus）中分离到两个腺苷酸环化酶基因（cyaA和cyaB）。预测的cyaA和cyaB基因产物具有与受体型腺苷酸环化酶的结构相似性，所述受体型腺苷酸环化酶由腺苷酸环化酶的氨基末端传感结构域和羧基末端催化结构域组成。一个cyaA突变体，放置在高离子（NaCl）或高非离子（蔗糖）胁迫的条件下，孢子形成和孢子萌发表现出显着减少。在营养细胞中，cyaA突变体对渗透胁迫反应正常。另一方面，破坏cyaB产生的突变体，显示在高离子（NaCl）或高非离子（蔗糖）渗透压生长迟缓。在非离子胁迫下，cyaB突变体的孢子萌发率显著低于cyaA突变体，但在非离子胁迫下，cyaB突变体的孢子萌发率显著高于cyaA突变体。这些结果表明M.黄花菜CyaA和CyaB主要在发育和孢子萌发过程中起着光合传感器的作用， ...更多信息在M.其次，我们从一株M.利用基于cAMP依赖性蛋白激酶（PKA）调节亚基的保守cAMP结合结构域设计的寡核苷酸探针，该克隆含有一个开放阅读框，cbpB，编码一个亲水性蛋白质与两个cAMP结合域。CbpB与PKA调节亚基具有部分一级结构相似性。cbpB突变株生长发育正常，孢子萌发正常。然而，在高温或低温条件下培养的cbpB突变体表现出显着的生长减少。cbpB突变体细胞也比野生型细胞对渗透胁迫更敏感。cbpB突变体的表型与某些真核微生物PKA调节亚基突变体的表型相似。这些结果表明，cAMP介导的信号转导途径在M. xanthus cAMP介导的信号转导途径在细菌中未见报道。少