The rare actinomycete Actinoplanes missouriensis forms terminal sporangia containing a few hundred flagellated spores. In response to water, the sporangia open and release the spores into external environments. The orphan response regulator TcrA functions as a global transcriptional activator during sporangium formation and dehiscence. Here, we report the characterization of an orphan hybrid histidine kinase, HhkA. Sporangia of an hhkA deletion mutant contained many distorted or ectopically germinated spores and scarcely opened to release the spores under sporangium dehiscence-inducing conditions. These phenotypic changes are quite similar to those observed in a tcrA deletion mutant. Comparative RNA sequencing analysis showed that genes controlled by HhkA mostly overlap TcrA-regulated genes. The direct interaction between HhkA and TcrA was suggested by a bacterial two-hybrid assay, but this was not conclusive. The phosphorylation of TcrA using acetyl phosphate as a phosphate donor markedly enhanced its affinity for the TcrA box sequences in the electrophoretic mobility shift assay. Taking these observations together with other results, we proposed that HhkA and TcrA compose a cognate two-component regulatory system, which controls the transcription of the genes involved in many aspects of morphological development, including sporangium formation, spore dormancy, and sporangium dehiscence in A. missouriensis.

中文翻译：

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密苏里游动动动菌中混合传感器组氨酸激酶对孢子囊形成、孢子休眠和孢子囊开裂的调节：与全局转录调节因子 TcrA 的关系。


稀有放线菌密苏里游动放线菌形成含有数百个有鞭毛孢子的末端孢子囊。为了响应水，孢子囊打开并将孢子释放到外部环境中。孤儿反应调节因子 TcrA 在孢子囊形成和开裂过程中充当全局转录激活因子。在这里，我们报告了孤儿杂合组氨酸激酶 HhkA 的特征。 hhkA缺失突变体的孢子囊含有许多扭曲或异位萌发的孢子，并且在孢子囊开裂诱导条件下几乎不打开释放孢子。这些表型变化与tcrA缺失突变体中观察到的非常相似。比较RNA测序分析表明，HhkA控制的基因大部分与TcrA调节的基因重叠。细菌双杂交试验表明 HhkA 和 TcrA 之间存在直接相互作用，但这并不是结论性的。在电泳迁移率变动测定中，使用乙酰磷酸作为磷酸供体的 TcrA 磷酸化显着增强了其对 TcrA 盒序列的亲和力。将这些观察结果与其他结果结合起来，我们提出HhkA和TcrA组成了一个同源的双组分调控系统，它控制着参与形态发育许多方面的基因的转录，包括孢子囊形成、孢子休眠和孢子囊开裂。 . 密苏里州。