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Diversity of the structures and functions of Streptomyces linear genomes

链霉菌线性基因组结构和功能的多样性

基本信息

批准号：
16208010
负责人：
KINASHI Haruyasu
金额：
$ 32.03万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

(1) We revealed that the chromosomal inversion found in Streptomycesgriseus 402-2 occurred by transposition of a transposonfollowedbyhomologousrecombinationbetweenthe old and new transposons.Consequently, we identified chimeric direct repeat sequences at both ends of the two transposons in strain 402-2.(2) We revealed that a series of linear plasmids in S. violaceoruber JCM4979 were formed by amplification of a 36-kb DNA unit comprising of SCP1 and SCP2 fragments in SCP1. It is quite interesting that these linear plasmids are compatible in spite of their identical oriC sequence.(3) The structure of LC-KA05 produced by an amine oxidasemutantof S. rochefindicated that oxidation of an amide intermediate to an imide followed by nucleophilic attack by C2 formed the unique 17-membered ring of lankacidin. Heterologous expression of the Ikc cluster in S. lividans and the lkcFG gene fusion experiment supported our modular-iterative polyketide biosynthesis hypothesis for lankacidin.(4) Feeding and gene targeting experiments revealed that isoleucine was oxidized to 2-methylbutyrate and incorporated into the 8,15-didexylankanolide skeleton, and then hydroxylated at the 15 and 8 positions by LkmK and LkmF, respectively.(5) We revealed that srrX-srrA make a y-butyrolactone-receptor system in S. rochei. The srrX gene showed a positive effect on antibiotic production and a negative effect on spore formation, while, srrA reversed both effects of srrX. Extensive transcriptional analysis confirmed the signaling pathway from srrX through srrA to srrY. We also identified two SrrA binding sites upstream of the srrY gene, which contained a palindromic sequence for GB-receptors and repeat sequences for SARP proteins, respectively.

(1)我们发现在Streptomycesgriseus 402-2中发现的染色体反转是由转座子的转位以及新旧转座子之间的同源重组引起的。因此，我们在菌株402-2的两个转座子的两端发现了嵌合直接重复序列。(2)通过在S. violaceoruber JCM4979中扩增由SCP1和SCP2片段组成的36 kb DNA单元，发现了一系列线性质粒。有趣的是，尽管这些线性质粒的oriC序列相同，但它们是相容的。(3)由罗氏霉胺氧化变异体生成的LC-KA05的结构表明，在C2的亲核攻击下，酰胺中间体被氧化为亚胺，形成独特的17元lankacidin环。lividans中Ikc簇的异源表达和lkcFG基因的融合实验支持了lankacidin的模块化迭代聚酮生物合成假说。(4)饲养和基因靶向实验表明，异亮氨酸被氧化成2-甲基丁酸酯，并结合到8,15-二脱氧烷醇内酯骨架中，然后分别在15位和8位被LkmK和LkmF羟基化。(5)发现srrX-srrA在罗氏菌中形成y-丁内酯受体体系。srrX基因对抗生素的产生有积极作用，对孢子的形成有消极作用，而srrA则逆转了srrX的这两种作用。广泛的转录分析证实了srrX通过srrA到srrY的信号通路。我们还鉴定了srrY基因上游的两个SrrA结合位点，它们分别包含gb受体的回文序列和SARP蛋白的重复序列。