Isolation and characterization of mutants defective for suborganellar localization of LCIB, an essential factor for carbon-concentrating mechanism in Chlamydomonas reinhardtii.
Isolation and characterization of mutants defective for suborganellar localization of LCIB, an essential factor for carbon-concentrating mechanism in Chlamydomonas reinhardtii.
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LCIB 亚细胞器定位缺陷突变体的分离和表征，LCIB 是莱茵衣藻碳浓缩机制的重要因素。
DOI：
10.1007/s11120-013-9963-6
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Hideya Fukuzawa*
中科院分区：
文献类型：
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作者：
Takashi Yamano;Atsuko Asada;Emi Sato;Hideya Fukuzawa*
单细胞绿藻achlamydomonasreinhardtiti适应低二氧化碳（LC）条件，通过主动将无机碳（Ci）运输到细胞中，从而提高光合效率。这种机制被称为碳浓缩机制（CCM），可溶性蛋白LCIB对CCM至关重要。在光照条件下，LCIB定位于叶绿体中一个突出的结构——类pyrenoid的附近。相反，在黑暗或高二氧化碳条件下，CCM是不活跃的，LCIB从类pyrenal扩散出去。虽然LCIB对CCM的功能重要性已被证明，但LCIB亚细胞质定位变化的意义和机制仍有待阐明。在这项研究中，我们筛选了13000个dna标记的突变体，并在LC条件下分离出12个异常的LCIB定位（abl）突变体。随着LCIB在叶绿体中的分散和斑点化定位，abl-1和abl-3的Ci亲和力、Ci积累和co2固定显著降低。突变体（abl-1、abl-3、abl-4、abl-5、abl-6、abl-7、abl-8、abl-9、abl-11和abl-12）不仅表现出LCIB定位异常，而且显示出类pyrenoid大小减小。此外，三个突变体（abl-10、abl-11和abl-12）显示每个细胞中类pyrenox的数量增加。这些结果提示LCIB的特异定位可能与类pyrenoid的发育有关。
The unicellular green algaChlamydomonasreinhardtiiacclimates to low-CO2(LC) conditions by actively transporting inorganic carbon (Ci) into the cell, resulting in an increase in photosynthetic efficiency. This mechanism is called the carbon-concentrating mechanism (CCM), and soluble protein LCIB is essential for the CCM. LCIB is localized in the vicinity of pyrenoid, a prominent structure in the chloroplast, under LC conditions in the light. In contrast, in the dark or in high-CO2conditions, where the CCM is inactive, LCIB diffuses away from the pyrenoid. Although the functional importance of LCIB for the CCM has been shown, the significance and mechanism of the change in suborganellar localization of LCIB remain to be elucidated. In this study, we screened 13,000 DNA-tagged mutants and isolated twelve aberrant LCIB localization (abl) mutants under LC conditions.abl-1andabl-3with dispersed and speckled localization of LCIB in the chloroplast showed significant decreases in Ci affinity, Ci accumulation, and CO2fixation. Tenablmutants (abl-1,abl-3,abl-4,abl-5,abl-6,abl-7,abl-8,abl-9,abl-11, andabl-12) showed not only aberrant LCIB localization but also reduced pyrenoid sizes. Moreover, threeablmutants (abl-10,abl-11, andabl-12) showed the increased numbers of pyrenoids per cell. These results suggested that the specific LCIB localization could be related to pyrenoid development.