PipX, the coactivator of NtcA, is a global regulator in cyanobacteria
PipX, the coactivator of NtcA, is a global regulator in cyanobacteria
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DOI：
10.1073/pnas.1404097111
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发表时间：
2014-06-10
影响因子：
11.1
通讯作者：
Contreras, Asuncion
中科院分区：
文献类型：
--
作者：
Espinosa, Javier;Rodriguez-Mateos, Francisco;Contreras, Asuncion
为了调节参与氮同化的基因的表达，蓝藻P-II相互作用蛋白X （PipX）与全球转录调节剂NtcA和信号转导蛋白P-II相互作用，P-II是一种存在于生命所有三个领域的蛋白质，作为氮和碳平衡信号的整合者。PipX可以与NtcA和P-II形成交替的复合物，这些相互作用分别被2-氧葡萄糖酸盐刺激和抑制，提供了P-II信号传导和NtcA调节的基因表达之间的机制联系。在这里，我们证明PipX参与了一个更广泛的相互作用网络。通过RNA测序，研究了pipX等位基因对硝态氮和铵态氮条件下生长的S. elongatus菌株转录物水平的影响，并对相关突变体/对照进行了多变量分析。通过这一过程，222个基因被划分为6组差异调节基因，其中两组含有ntca激活或ntca抑制的基因，这为NtcA-PipX复合物的功能提供了进一步的了解。其余四组表明PipX参与至少三个不依赖于ntca的调控途径。我们的研究结果为揭示蓝藻中基因表达控制的新调控相互作用和机制铺平了道路。
To modulate the expression of genes involved in nitrogen assimilation, the cyanobacterial P-II-interacting protein X (PipX) interacts with the global transcriptional regulator NtcA and the signal transduction protein P-II, a protein found in all three domains of life as an integrator of signals of the nitrogen and carbon balance. PipX can form alternate complexes with NtcA and P-II, and these interactions are stimulated and inhibited, respectively, by 2-oxoglutarate, providing a mechanistic link between P-II signaling and NtcA-regulated gene expression. Here, we demonstrate that PipX is involved in a much wider interaction network. The effect of pipX alleles on transcript levels was studied by RNA sequencing of S. elongatus strains grown in the presence of either nitrate or ammonium, followed by multivariate analyses of relevant mutant/control comparisons. As a result of this process, 222 genes were classified into six coherent groups of differentially regulated genes, two of which, containing either NtcA-activated or NtcA-repressed genes, provided further insights into the function of NtcA-PipX complexes. The remaining four groups suggest the involvement of PipX in at least three NtcA-independent regulatory pathways. Our results pave the way to uncover new regulatory interactions and mechanisms in the control of gene expression in cyanobacteria.