Molecular and cellular profiles of insect bacteriocytes:: mutualism and harm at the initial evolutionary step of symbiogenesis
Molecular and cellular profiles of insect bacteriocytes:: mutualism and harm at the initial evolutionary step of symbiogenesis
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DOI：
10.1111/j.1462-5822.2004.00461.x
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发表时间：
2005-02-01
影响因子：
3.4
通讯作者：
Wäckers, F
中科院分区：
文献类型：
--
作者：
Heddi, A;Vallier, A;Wäckers, F
细胞内共生被认为是真核细胞进化的驱动力。在昆虫中，人们对携带细菌的宿主细胞（细菌细胞）的分子基础知之甚少，特别是在共生的初始步骤中，由于与细胞内和垂直传播相关的进化限制，细菌基因组没有经历严重的基因缺失。在这里，我们对最近建立的内共生体象鼻虫玉米象甲的细菌细胞应用聚合酶链反应（PCR）减去 cDNA 和反向 Northern 分析，以发现与细菌细胞遗传学潜在相关的基因。我们提供了细菌细胞对细胞内细菌转录反应的广泛特征，包括代谢-转运-应激（MTS）、细胞信号传导和运输、生长和凋亡以及先天免疫的途径。 MTS 基因显示出与压力增加相关的有趣的类似糖尿病的致病特征，碳水化合物转运蛋白、醛糖还原酶和压力相关基因的高水平上调表明了这一点。对组织碳水化合物含量的高效液相色谱 (HPLC) 分析强调了共生昆虫中碳水化合物同化的增加以及多元醇生物合成途径的普遍存在，如山梨醇、甘露醇和果糖在细菌细胞中的积累所表明的。这些发现为昆虫与合作细菌之间相互作用的本质提供了第一个遗传学视角。他们揭示了与新陈代谢和细胞运输增加相关的深刻的昆虫细菌细胞应激，并揭示了先天免疫在昆虫共生初始阶段的病原互惠转变过程中的潜在作用。
Intracellular symbiosis is considered to be a driving force in eukaryotic cell evolution. In insects, little is known about the molecular bases of the bacteria-bearing host cells (bacteriocytes), particularly in the initial steps of symbiosis, where the bacterial genome has not experienced severe gene deletions because of evolutionary constraints associated with intracellular and vertical transmission. Here, we have applied polymerase chain reaction (PCR)-subtracted cDNA and reverse Northern analysis on the bacteriocytes of a recently established endosymbiosis, the weevil Sitophilus zeamais, to discover genes of potential relevance to bacteriocyte genetics. We provide a broad characterization of bacteriocyte transcriptional responses to intracellular bacteria, including pathways covering metabolism-transport-stress (MTS), cell signalling and trafficking, growth and apoptosis, as well as innate immunity. MTS genes show an intriguing diabetes-like pathogenic profile associated with increased stress, as indicated by high levels of upregulations of carbohydrate transporters, aldose reductases and stress-related genes. A high-performance liquid chromatography (HPLC) analysis of tissue carbohydrate contents highlighted an increased carbohydrate assimilation in symbiotic insects and the prevalence of a polyol biosynthetic pathway, as indicated by the accumulation of sorbitol, mannitol and fructose in the bacteriocytes. These findings provide the first genetic perspectives on the nature of the interaction between insect and cooperative bacteria. They unravel the profound insect bacteriocyte stress associated with increased metabolism and cell trafficking, and they shed light on the potential role of the innate immunity during the pathogeny-mutualism transition at the initial stage of insect symbiogenesis.