Developmental control of a parAB promoter leads to formation of sporulation-associated ParB complexes in Streptomyces coelicolor
Developmental control of a parAB promoter leads to formation of sporulation-associated ParB complexes in Streptomyces coelicolor
复制标题
DOI：
10.1128/jb.188.5.1710-1720.2006
复制
发表时间：
2006-03-01
影响因子：
3.2
通讯作者：
Chater, KF
中科院分区：
文献类型：
--
作者：
Jakimowicz, D;Mouz, S;Chater, KF
天蓝色链霉菌PARB蛋白与线形染色体ORIC-近端的许多PARS结合。PARB结合导致形成大的复合体，这些复合体在复杂的生命周期中表现不同(D.Jakimowicz，B.Gust，J.Zakrzewska-Czerwinska，和K.F.Chater，J.细菌素)。187：3572-3580,2005)。在这里，我们分析了支持这种发育特异性行为的转录调控。对启动子突变的分析表明，营养菌丝中存在的不规则间隔的复合体依赖于构成的parABp(1)启动子，而启动子parABp(2)的孢子形成特异性诱导是气生菌丝组装PARB复合体阵列所必需的，因此是有效的染色体分离所必需的。ParABp(2)的表达完全依赖于两个产孢子调控基因WhiA和WhiB，部分依赖于另外两个基因WhiH和WhiI，这四个基因都是产孢子分裂所必需的。由于这种依赖模式，我们研究了WhiA和WhiB突变体中这四个Whi基因的转录，揭示了WhiA和WhiB之间显著的调控相互作用。一个菌株的孢子形成分离(而不是营养分离)被孢子形成特异性启动子FtsZ的突变阻断，显示出接近野生型诱导的parABp(2)，并在气生菌丝中形成相当规则的PARB增强的绿色荧光蛋白焦点，排除了在孢子形成过程中分离和DNA分配之间强烈的形态耦合或检查点调节。提出了parABp(2)表达的发育调控模型。
The Streptomyces coelicolor partitioning protein ParB binds to numerous parS sites in the oriC-proximal part of the linear chromosome. ParB binding results in the formation of large complexes, which behave differentially during the complex life cycle (D. Jakimowicz, B. Gust, J. Zakrzewska-Czerwinska, and K. F. Chater, J. Bacteriol. 187:3572-3580, 2005). Here we have analyzed the transcriptional regulation that underpins this developmentally specific behavior. Analysis of promoter mutations showed that the irregularly spaced complexes present in vegetative hyphae are dependent on the constitutive parABp(1) promoter, while sporulation-specific induction of the promoter parABp(2) is required for the assembly of arrays of ParB complexes in aerial hyphae and thus is necessary for efficient chromosome segregation. Expression from parABp(2) depended absolutely on two sporulation regulatory genes, whiA and whiB, and partially on two others, whiH and whiI, all four of which are needed for sporulation septation. Because of this pattern of dependence, we investigated the transcription of these four whi genes in whiA and whiB mutants, revealing significant regulatory interplay between whiA and whiB. A strain in which sporulation septation (but not vegetative septation) was blocked by mutation of a sporulation-specific promoter of ftsZ showed close to wild-type induction of parABp(2) and formed fairly regular ParB-enhanced green fluorescent protein foci in aerial hyphae, ruling out strong morphological coupling or checkpoint regulation between septation and DNA partitioning during sporulation. A model for developmental regulation of parABp(2) expression is presented.