Phylogenetic analysis indicates multiple origins of chloroplast glyceraldehyde-3-phosphate dehydrogenase genes in dinoflagellates.
Phylogenetic analysis indicates multiple origins of chloroplast glyceraldehyde-3-phosphate dehydrogenase genes in dinoflagellates.
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系统发育分析表明甲藻中叶绿体甘油醛-3-磷酸脱氢酶基因的多个起源。
DOI：
10.1093/oxfordjournals.molbev.a004178
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发表时间：
2002
影响因子：
10.7
通讯作者：
WoodlandHastings,J
中科院分区：
文献类型：
--
作者：
Fagan,ThomasF;WoodlandHastings,J
虽然内共生进化理论（Margulis 1970）被广泛接受，但导致线粒体和叶绿体永久包含在真核细胞中的一系列事件却知之甚少。特别是，叶绿体的不同生化和形态特性导致了这些细胞器是通过多个初级内共生事件获得的建议（回顾见Delwiche 1999）。此外，在某些叶绿体周围存在三层，有时是四层（Gibbs 1962）膜，其中一些与第二个核相关，这表明次生内共生也发生了，即真核生物内部整合了来自另一个真核生物的可遗传细胞器（Gibbs 1981）。次生内共生也可能不止一次发生（Delwiche and Palmer 1997; Delwiche 1999）；事实上，不能排除一些自养真核生物失去了光合作用细胞器，只是在后来的内共生事件中重新获得它们的可能性。只有在宿主细胞中保留了第一个内共生体的一些残余物时，才能证明这种多重连续内共生事件的发生。叶绿体蛋白的核编码基因，例如GAPDH，可以提供这样的证据。虽然系统发育分析已经将细胞质（GapC）和叶绿体（GapA）序列划分为两个不同的分支（Martin et al. 1993; Liaud et al. 1997），但最近对海藻中gapdh亚型的研究使简单的细胞质-叶绿体树结构变得复杂。在鞭毛藻Lingulodinium polydrum (Stein) Dodge（原Gonyaulax polydra）和两种隐单胞菌（Guillardia theta和Pyrenomonas salina）中，GAPDH在卡尔文循环中的作用由修饰的细胞质异构体（GapC-I）填补，该异构体在n端有一个信号序列，用于细胞内转运到叶绿体，并且与其合成代谢作用一致，氨基酸取代允许NADPH结合（Liaud et al. 1997; Fagan, Hastings, and Morse 1998）。系统发育分析将gapc - 1确定为细胞质分支（Fagan, Hastings, and Morse 1998）。随后，在异孔体和顶复体中发现了同源异构体（Liaud et al. 2000; Fast et al. 2001）。gapc - 1异构体是如何获得的以及它在鞭毛藻中的普遍程度尚不清楚。我们认为它是通过横向转移获得的
Although the endosymbiotic theory of evolution (Margulis 1970) is widely accepted, the series of events that led to the permanent inclusion of mitochondria and chloroplasts in eukaryotic cells are poorly understood. In particular, the diverse biochemical and morphological properties of chloroplasts have led to suggestions that these organelles have been acquired through multiple primary endosymbiotic events (for a review see Delwiche 1999). Furthermore, the presence of three and sometimes four (Gibbs 1962) membranes around certain chloroplasts, some in association with a second nucleus, suggests that secondary endosymbiosis—the incorporation within a eukaryote of a heritable organelle from another eukaryote—has also occurred (Gibbs 1981). Secondary endosymbioses may also have occurred more than once (Delwiche and Palmer 1997; Delwiche 1999); in fact, the possibility that some autotrophic eukaryotes lost their photosynthetic organelles only to regain them in a later endosymbiotic event cannot be excluded. The occurrence of such multiple, sequential endosymbiotic events can only be proven if some remnant of the first endosymbiont was retained by the host cell. Nuclearencoded genes for chloroplast proteins, for example GAPDH, could provide such evidence. Although phylogenetic analyses have resolved cytosolic (GapC) and chloroplast (GapA) sequences into two distinct clades (Martin et al. 1993; Liaud et al. 1997), recent studies of gapdh isoforms from marine algae have complicated the simple cytosol-chloroplast tree structure. In the dinoflagellate Lingulodinium polyedrum (Stein) Dodge, formerly Gonyaulax polyedra, and in two cryptomonads (Guillardia theta and Pyrenomonas salina) the role of GAPDH in the Calvin cycle is filled by a modified cytosolic isoform (GapC-I), which has a signal sequence at the N-terminal end for intracellular translocation to the chloroplast and, consistent with its anabolic role, amino acid substitutions that allow binding of NADPH (Liaud et al. 1997; Fagan, Hastings, and Morse 1998). Phylogenetic analysis places GapC-I firmly in the cytosolic clade (Fagan, Hastings, and Morse 1998). Homologous isoforms have been identified subsequently in heterokonts and apicomplexans (Liaud et al. 2000; Fast et al. 2001). How the GapC-I isoform was acquired and how pervasive it is among dinoflagellates is unknown. We proposed that it was obtained through lateral transfer