A connection between stress and development in the multicellular prokaryote Streptomyces coelicolor A3(2)
A connection between stress and development in the multicellular prokaryote Streptomyces coelicolor A3(2)
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DOI：
10.1046/j.1365-2958.2001.02417.x
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发表时间：
2001-05-01
影响因子：
3.6
通讯作者：
Thompson, CJ
中科院分区：
文献类型：
--
作者：
Kelemen, GH;Viollier, PH;Thompson, CJ
导致菌丝体细菌天蓝色链霉菌气生菌丝体形成和孢子形成的形态变化依赖于在殖民地的不同区域中建立不同的基因表达模式。sigma（H）是S.在这里，我们发现sigH和上游基因prsH（编码sigma（H）的假定的抗sigma因子）形成由两个发育调节启动子sigHp 1和sigHp 2转录的操纵子，而sigHp 1活性仅限于生长的早期阶段，sigHp 2的转录在气生菌丝形成时被显著诱导。利用与绿色荧光蛋白报告基因（sigHp 2-egfp）的转录融合定位sigHp 2的活性表明，sigHp 2的转录在空间上局限于野生型S.然而，对不能形成气生菌丝的突变体（bld突变体）的分析表明，在bldD突变体中sigHp 2转录和sigma（H）蛋白水平显著上调，并且sigHp 2-egfp融合体在bldD背景下的基质菌丝体中异位表达。天蓝色，显示为BldD。通过DNA酶I足迹法确定sigHp 2启动子中的BldD结合位点。这些数据表明，在菌落发育过程中，sigma（H）的表达受到时间和空间调节，这种组织特异性调节直接由发育转录因子BldD介导，并表明应力和发育程序可能在链霉菌形态发生中密切相关。
Morphological changes leading to aerial mycelium formation and sporulation in the mycelial bacterium Streptomyces coelicolor rely on establishing distinct patterns of gene expression in separate regions of the colony. sigma (H) was identified previously as one of three paralogous sigma factors associated with stress responses in S. coelicolor, Here, we show that sigH and the upstream gene prsH (encoding a putative antisigma factor of sigma (H)) form an operon transcribed from two developmentally regulated promoters, sigHp1 and sigHp2, While sigHp1 activity is confined to the early phase of growth, transcription of sigHp2 is dramatically induced at the time of aerial hyphae formation. Localization of sigHp2 activity using a transcriptional fusion to the green fluorescent protein reporter gene (sigHp2-egfp) showed that sigHp2 transcription is spatially restricted to sporulating aerial hyphae in wild-type S. coelicolor, However, analysis of mutants unable to form aerial hyphae (bld mutants) showed that sigHp2 transcription and sigma (H) protein levels are dramatically upregulated in a bldD mutant, and that the sigHp2-egfp fusion was expressed ectopically in the substrate mycelium in the bldD background, Finally, a protein possessing sigHp2 promoter-binding activity was purified to homogeneity from crude mycelial extracts of S. coelicolor and shown to be BldD. The BldD binding site in the sigHp2 promoter was defined by DNase I footprinting. These data show that expression of sigma (H) is subject to temporal and spatial regulation during colony development, that this tissue-specific regulation is mediated directly by the developmental transcription factor BldD and suggest that stress and developmental programmes may be intimately connected in Streptomyces morphogenesis.