Functional Overlap of hetP and hetZ in Regulation of Heterocyst Differentiation in Anabaena sp Strain PCC 7120
Functional Overlap of hetP and hetZ in Regulation of Heterocyst Differentiation in Anabaena sp Strain PCC 7120
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hetP 和 hetZ 在鱼腥藻菌株 PCC 7120 异囊分化调节中的功能重叠
DOI：
10.1128/jb.00707-17
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发表时间：
2018
影响因子：
3.2
通讯作者：
Xu Xudong
中科院分区：
文献类型：
--
作者：
Zhang He;Wang Shuai;Wang Yali;Xu Xudong
HetR在鱼腥藻异形胞分化和模式化的调控中起着关键作用。它直接调节参与异形胞分化的基因（如ashetPandhetZ），参与模式形成的基因（patA）以及许多其他基因。在这项研究中，我们研究了hetPandhetZ的功能关系和它们在HetR依赖的细胞分化中的作用。从ntcA启动子共表达的hetPandhetZ，它编码的全局氮调节，使ahetR突变体形成异型胞与低好氧固氮酶活性。hetZ的过表达恢复了ahetP突变体的异形胞分化，反之亦然。hetR的过表达恢复了ahetP或ahetZ突变体中的异形胞形成，但不能恢复ahetZ hetP双突变体中的异形胞形成。通过逆转录-定量PCR（RT-qPCR）和转录组学分析它们对基因表达的影响，进一步证实了hetPandhetZ的功能重叠。此外，酵母双杂交和pulldown实验表明HetZ与HetR之间存在相互作用。HetP和HetZ提出的两个主要因素，控制异形胞形成的上调ofhetR. IMPORTANCEHeterocysts形成蓝藻有助于显着N2固定在海洋，淡水和陆地生态系统。异形胞的形成使这组蓝藻在有氧条件下能够有效地固定N2。HetR、HetP和HetZ是参与异形胞分化的最重要的因子之一。我们提出的证据hetPandhetZ的功能重叠和HetR-HetP/HetZ电路在异形胞分化的调节中的关键作用。基于HetR、HetP和HetZ的调控机制可能在所有形成杂胞的蓝藻中是保守的。
HetR plays a key role in regulation of heterocyst differentiation and patterning in Anabaena. It directly regulates genes involved in heterocyst differentiation (such ashetPandhetZ), genes involved in pattern formation (patA), and many others. In this study, we investigated the functional relationship ofhetPandhetZand their role in HetR-dependent cell differentiation. Coexpression ofhetPandhetZfrom the promoter ofntcA, which encodes the global nitrogen regulator, enabled ahetRmutant to form heterocysts with low aerobic nitrogenase activity. Overexpression ofhetZrestored heterocyst differentiation in ahetPmutant and vice versa. Overexpression ofhetRrestored heterocyst formation in either ahetPor ahetZmutant but not in ahetZ hetPdouble mutant. The functional overlap ofhetPandhetZwas further confirmed by reverse transcription-quantitative PCR (RT-qPCR) and transcriptomic analyses of their effects on gene expression. In addition, yeast two-hybrid and pulldown assays showed the interaction of HetZ with HetR. HetP and HetZ are proposed as the two major factors that control heterocyst formation in response to upregulation ofhetR.IMPORTANCEHeterocyst-forming cyanobacteria contribute significantly to N2fixation in marine, freshwater, and terrestrial ecosystems. Formation of heterocysts enables this group of cyanobacteria to fix N2efficiently under aerobic conditions. HetR, HetP, and HetZ are among the most important factors involved in heterocyst differentiation. We present evidence for the functional overlap ofhetPandhetZand for the key role of the HetR-HetP/HetZ circuit in regulation of heterocyst differentiation. The regulatory mechanism based on HetR, HetP, and HetZ is probably conserved in all heterocyst-forming cyanobacteria.