Molecular phylogeny and evolution of the plastid and nuclear encoded cbbX genes in the unicellular red alga Cyanidioschyzon merolae
Molecular phylogeny and evolution of the plastid and nuclear encoded cbbX genes in the unicellular red alga Cyanidioschyzon merolae
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DOI：
10.1266/ggs.83.127
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发表时间：
2008-04-01
影响因子：
1.1
通讯作者：
Ohta, Niji
中科院分区：
文献类型：
--
作者：
Fujita, Kiyohito;Ehira, Shigeki;Ohta, Niji
cbbX 基因通常编码于变形菌基因组和红藻质体基因组中。在这项研究中，我们发现了 Cyanidioschyzon merolae（一种单细胞红藻）的两个不同的 cbbX 基因，一个在质体基因组中编码，另一个在细胞核中编码。从cbbX基因和高度保守的基因组织（rbcLS-cbbX）推断出的系统发育树表明，C. merolae的质体编码的cbbX基因通过水平基因转移来自祖先变形菌。另一方面，C. merolae 的核编码 cbbX 基因与 Guillardia theta 的核形态编码 cbbX 基因一起被分类在另一个簇中。此外，两个 cbbX 基因的表达因细胞外 CO2 浓度而受到不同的调节。我们的结果表明，在相对较早的阶段，质体基因组中的cbbX基因在来自祖先β-变形菌的RuBisCo操纵子的水平基因转移后被复制并转移到细胞核中，并且每个cbbX以不同的方式进化。
The cbbX gene is generally encoded in proteobacterial genomes and red-algal plastid genomes. In this study, we found two distinct cbbX genes of Cyanidioschyzon merolae, a unicellular red alga, one encoded in the plastid genome and the other encoded in the cell nucleus. The phylogenetic tree inferred from cbbX genes and strongly conserved gene organization (rbcLS-cbbX) suggests that the plastid-encoded cbbX gene of C. merolae came from an ancestral proteobacterium by horizontal gene transfer. On the other hand, the nuclear-encoded cbbX gene of C. merolae was classified in another cluster together with the nucleomorph-encoded cbbX gene of Guillardia theta. Furthermore, expression of the two cbbX genes were regulated differently in response to extracellular CO2 concentration. Our results imply that cbbX gene in the plastid genome was copied and transferred to the cell nucleus after horizontal gene transfer of RuBisCo operon from ancestral beta-proteobacteria at comparatively early stage, and that each cbbX evolved in different ways.