Regulation of Sporangium Formation by BldD in the Rare Actinomycete Actinoplanes missouriensis
Regulation of Sporangium Formation by BldD in the Rare Actinomycete Actinoplanes missouriensis
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DOI：
10.1128/jb.00840-16
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发表时间：
2017-06-01
影响因子：
3.2
通讯作者：
Ohnishi, Yasuo
中科院分区：
文献类型：
--
作者：
Mouri, Yoshihiro;Konishi, Kenji;Ohnishi, Yasuo
罕见的放线菌Actinoplanes missouriensis形成孢子囊，包括数百个鞭毛孢子，释放后开始游泳作为游动孢子。在适合营养生长的条件下，游动孢子停止游动并萌发。游动孢子和萌发细胞之间的比较蛋白质组分析确定了15种蛋白质，在萌发细胞中产生的大量。它们包括BldD的直向同源物（本文称为AmBldD [A. missouriensis]），其是链霉菌中参与形态发育和次级代谢的转录调节因子。AmBldD在营养生长期间在菌丝体中检测到，但在孢子囊形成阶段期间在菌丝体中几乎没有检测到，尽管AmbldD在整个生长过程中不断转录。AmbldD突变体比野生型菌株更早开始形成孢子囊，并且所产生的孢子囊在形态上异常。重组AmBldD结合位于AmbldD上游的回文序列，AmBldD盒。3 '，5'-环二GMP显著增强AmBldD的体外DNA结合能力。染色质免疫沉淀-测序分析和AmBldD盒的计算机搜索显示AmBldD结合346个基因组位点，其包含19 bp反向重复5 '-NN（G/A）TNACN（C/G）N（G/C）NGTNA（C/T）NN-3'作为AmBldD结合序列。对27个选定的AmBldD靶基因候选者的转录分析表明，AmBldD应该抑制27个基因中的12个，包括bldM、ssgB、whiD、ddbA和wblA直系同源物。这些基因参与天蓝色链霉菌A3的形态发育（2）。因此，AmBldD是一个全球性的转录调节因子，似乎在营养生长过程中抑制数十个基因的转录，其中一些可能是所需的孢子囊formation.IMPORTANCE罕见的放线菌Actinoplanes密苏里经历复杂的形态分化，包括孢子囊的形成。然而，几乎没有对这种细菌进行分子生物学研究。BldD是参与链霉菌形态发育的关键全局调节因子。BldD直系同源物在产孢放线菌中是高度保守的，但除了一个在链霉菌中的BldD直系同源物外，没有研究过链霉菌。在此，揭示了BldD直向同源物AmBldD对于A.密苏里AmBldD调节子似乎与天蓝色链霉菌A3（2）中的BldD调节子不同，但它们共有四个参与S形态分化的基因。coelicolor A3（2）.
The rare actinomycete Actinoplanes missouriensis forms sporangia, including hundreds of flagellated spores that start swimming as zoospores after their release. Under conditions suitable for vegetative growth, zoospores stop swimming and germinate. A comparative proteome analysis between zoospores and germinating cells identified 15 proteins that were produced in larger amounts in germinating cells. They include an orthologue of BldD (herein named AmBldD [BldD of A. missouriensis]), which is a transcriptional regulator involved in morphological development and secondary metabolism in Streptomyces. AmBldD was detected in mycelia during vegetative growth but was barely detected in mycelia during the sporangium-forming phase, in spite of the constant transcription of AmbldD throughout growth. An AmbldD mutant started to form sporangia much earlier than the wild-type strain, and the resulting sporangia were morphologically abnormal. Recombinant AmBldD bound a palindromic sequence, the AmBldD box, located upstream from AmbldD. 3', 5'-Cyclic di-GMP significantly enhanced the in vitro DNA-binding ability of AmBldD. A chromatin immunoprecipitation-sequencing analysis and an in silico search for AmBldD boxes revealed that AmBldD bound 346 genomic loci that contained the 19-bp inverted repeat 5'-NN(G/A) TNACN(C/G) N(G/C) NGTNA(C/T) NN-3' as the consensus AmBldD-binding sequence. The transcriptional analysis of 27 selected AmBldD target gene candidates indicated that AmBldD should repress 12 of the 27 genes, including bldM, ssgB, whiD, ddbA, and wblA orthologues. These genes are involved in morphological development in Streptomyces coelicolor A3(2). Thus, AmBldD is a global transcriptional regulator that seems to repress the transcription of tens of genes during vegetative growth, some of which are likely to be required for sporangium formation.IMPORTANCE The rare actinomycete Actinoplanes missouriensis undergoes complex morphological differentiation, including sporangium formation. However, almost no molecular biological studies have been conducted on this bacterium. BldD is a key global regulator involved in the morphological development of streptomycetes. BldD orthologues are highly conserved among sporulating actinomycetes, but no BldD orthologues, except one in Saccharopolyspora erythraea, have been studied outside the streptomycetes. Here, it was revealed that the BldD orthologue AmBldD is essential for normal developmental processes in A. missouriensis. The AmBldD regulon seems to be different from the BldD regulon in Streptomyces coelicolor A3(2), but they share four genes that are involved in morphological differentiation in S. coelicolor A3(2).