A gene regulatory network for antenna size control in carbon dioxide-deprived Chlamydomonas reinhardtii cells.
A gene regulatory network for antenna size control in carbon dioxide-deprived Chlamydomonas reinhardtii cells.
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DOI：
10.1093/plcell/koab012
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发表时间：
2021-01
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通讯作者：
Olga Blifernez-Klassen;Hanna Berger;Birgit Gerlinde Katharina Mittmann;V. Klassen;Louise Schelletter;T. Buchholz;T. Baier;Maryna Soleimani;Lutz Wobbe;O. Kruse
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作者：
Olga Blifernez-Klassen;Hanna Berger;Birgit Gerlinde Katharina Mittmann;V. Klassen;Louise Schelletter;T. Buchholz;T. Baier;Maryna Soleimani;Lutz Wobbe;O. Kruse
在绿色微藻中，长期暴露于无机碳消耗需要长期的驯化反应，包括基因表达的调节和光合活性对二氧化碳主要供应的调整。在这里，我们描述了一个微藻调节循环，该循环调节光系统II （PSII）的光收集能力，以适应衣藻（莱茵衣藻）中二氧化碳的主要供应。它涉及低二氧化碳反应因子（LCRF）， squamosa启动子结合蛋白（SBP）家族转录因子的成员，以及先前表征的细胞质翻译抑制因子核酸结合蛋白1 （NAB1）。LCRF结合了dna结合的SBP结构域和蛋白相互作用的保守结构域。LCRF的转录可被二氧化碳耗尽迅速诱导。LCRF通过特异性结合其启动子中的四核苷酸基序来激活NAB1的转录。NAB1蛋白的积累增强了其主要靶mRNA的翻译抑制，该mRNA编码psii相关的主要光收集蛋白LHCBM6。由此产生的PSII天线尺寸的截断有助于在二氧化碳限制期间保持低激励。对缺乏功能性LCRF基因的核插入突变体的低二氧化碳驯化分析证实了这种新型转录因子对调控回路的重要性。
In green microalgae, prolonged exposure to inorganic carbon depletion requires long-term acclimation responses, involving modulated gene expression and the adjustment of photosynthetic activity to the prevailing supply of carbon dioxide. Here, we describe a microalgal regulatory cycle that adjusts the light-harvesting capacity at photosystem II (PSII) to the prevailing supply of carbon dioxide in Chlamydomonas (Chlamydomonas reinhardtii). It engages low carbon dioxide response factor (LCRF), a member of the squamosa promoter-binding protein (SBP) family of transcription factors, and the previously characterized cytosolic translation repressor nucleic acid-binding protein 1 (NAB1). LCRF combines a DNA-binding SBP domain with a conserved domain for protein-protein interaction. LCRF transcription is rapidly induced by carbon dioxide depletion. LCRF activates NAB1 transcription by specifically binding to tetranucleotide motifs present in its promoter. Accumulation of the NAB1 protein enhances translational repression of its prime target mRNA, encoding the PSII-associated major light-harvesting protein LHCBM6. The resulting truncation of the PSII antenna size helps maintaining a low excitation during carbon dioxide limitation. Analyses of low carbon dioxide acclimation in nuclear insertion mutants devoid of a functional LCRF gene confirm the essentiality of this novel transcription factor for the regulatory circuit.