The CO 2 concentrating mechanism (CCM) is a key feature of green algal cells, induced in response to limiting CO 2 conditions. Calcium-dependent signaling has been shown to play a role in this acclimation process to low inorganic carbon in Chlamydomonas reinhardtii , but the molecular players have not been characterized. One type of Ca 2+ channel, the transient receptor potential (TRP) family of ion channels is specific to the algal members of the green lineage and not found in land plants. TRP channels generally mediate the flux of Ca 2+ ions in response to environmental perturbations, and one recent study has revealed the role of Ca 2+ signaling in acclimation to limiting CO 2 in the green alga, C. reinhardtii . In this study, the gene Trp2 , encoding a Ca 2+ ion channel was identified through bioinformatics analyses as having a role in acclimation of algal cells to limiting CO 2 . Transcript abundance levels for this gene are significantly upregulated when cells are cultured in limiting CO 2 and mutant cells missing the TRP2 protein show an impaired growth phenotype. We show that a calcium binding protein CAS, is downregulated in the trp2 mutant along with other CCM genes under the control of CAS. The results suggest that the TRP2 ion channel is involved in the acclimation of C. reinhardtii cells to limiting CO 2 .

中文翻译：

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莱茵衣藻低 CO2 环境中瞬态受体电位离子通道 (TRP2) 的鉴定和表征

CO 2 浓缩机制 (CCM) 是绿藻细胞的一个关键特征，是响应限制性 CO 2 条件而诱导的。钙依赖性信号已被证明在莱茵衣藻对低无机碳的驯化过程中发挥作用，但尚未确定分子参与者的特征。一种类型的 Ca 2+ 通道，离子通道的瞬时受体电位 (TRP) 家族特定于绿色谱系的藻类成员，在陆地植物中未发现。TRP 通道通常介导 Ca 2+ 离子对环境扰动的反应，最近的一项研究揭示了 Ca 2+ 信号在适应限制绿藻莱茵藻中的 CO 2 中的作用。在这项研究中，基因 Trp2 ，编码Ca 2+ 离子通道的编码通过生物信息学分析被鉴定为在藻类细胞适应限制CO 2 中起作用。当细胞在限制性 CO 2 条件下培养并且缺少 TRP2 蛋白的突变细胞显示生长表型受损时，该基因的转录丰度水平显着上调。我们表明钙结合蛋白 CAS 在 trp2 突变体中与 CAS 控制下的其他 CCM 基因一起下调。结果表明，TRP2 离子通道参与了莱茵衣藻细胞对限制 CO 2 的驯化。在 trp2 突变体中与 CAS 控制下的其他 CCM 基因一起下调。结果表明，TRP2 离子通道参与了莱茵衣藻细胞对限制 CO 2 的驯化。在 trp2 突变体中与 CAS 控制下的其他 CCM 基因一起下调。结果表明，TRP2 离子通道参与了莱茵衣藻细胞对限制 CO 2 的驯化。