Department of Energy and Environmental Biotechnology, Division of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland.
Appl Environ Microbiol. 2018 Jul 17;84(15). doi: 10.1128/AEM.00771-18. Print 2018 Aug 1.
Genomic islands (GIs) are a type of mobile genetic element (MGE) that are present in bacterial chromosomes. They consist of a cluster of genes that produce proteins that contribute to a variety of functions, including, but not limited to, the regulation of cell metabolism, antimicrobial resistance, pathogenicity, virulence, and resistance to heavy metals. The genes carried in MGEs can be used as a trait reservoir in times of adversity. Transfer of genes using MGEs, occurring outside reproduction, is called horizontal gene transfer (HGT). Previous data have shown that numerous HGT events have occurred through endosymbiosis between prokaryotes and eukaryotes. β-Carbonic anhydrase (β-CA) enzymes play a critical role in the biochemical pathways of many prokaryotes and eukaryotes. We previously suggested the horizontal transfer of β-CA genes from plasmids of some prokaryotic endosymbionts to their protozoan hosts. In this study, we set out to identify β-CA genes that might have been transferred between prokaryotic and protist species through HGT in GIs. Therefore, we investigated prokaryotic chromosomes containing β-CA-encoding GIs and utilized multiple bioinformatics tools to reveal the distinct movements of β-CA genes among a wide variety of organisms. Our results identify the presence of β-CA genes in GIs of several medically and industrially relevant bacterial species, and phylogenetic analyses reveal multiple cases of likely horizontal transfer of β-CA genes from GIs of ancestral prokaryotes to protists. The evolutionary process is mediated by mobile genetic elements (MGEs), such as genomic islands (GIs). A gene or set of genes in the GIs is exchanged between and within various species through horizontal gene transfer (HGT). Based on the crucial role that GIs can play in bacterial survival and proliferation, they were introduced as environment- and pathogen-associated factors. Carbonic anhydrases (CAs) are involved in many critical biochemical pathways, such as the regulation of pH homeostasis and electrolyte transfer. Among the six evolutionary families of CAs, β-CA gene sequences are present in many bacterial species, which can be horizontally transferred to protists during evolution. This study shows the involvement of bacterial β-CA gene sequences in the GIs and suggests their horizontal transfer to protists during evolution.
基因岛 (GI) 是一种存在于细菌染色体中的移动遗传元件 (MGE)。它们由一组基因组成，这些基因产生的蛋白质有助于多种功能，包括但不限于细胞代谢、抗菌药物耐药性、致病性、毒力和重金属耐药性的调节。MGE 中携带的基因可以在逆境中作为性状库使用。MGE 介导的基因转移，即发生在繁殖之外的水平基因转移 (HGT)。先前的数据表明，许多 HGT 事件是通过原核生物和真核生物之间的共生关系发生的。β-碳酸酐酶 (β-CA) 酶在许多原核生物和真核生物的生化途径中发挥着关键作用。我们之前曾提出，β-CA 基因从一些原核共生体的质粒转移到其原生动物宿主。在这项研究中，我们着手确定通过 GI 中的 HGT 在原核生物和原生生物物种之间转移的 β-CA 基因。因此，我们研究了含有编码 GI 的 β-CA 的原核染色体，并利用多种生物信息学工具来揭示 β-CA 基因在广泛的生物体中的不同运动。我们的结果确定了几种具有医学和工业相关性的细菌物种的 GI 中存在 β-CA 基因，并且系统发育分析揭示了来自祖先原核生物 GI 的 β-CA 基因可能从 GI 到原生动物的多次水平转移。进化过程是由移动遗传元件（MGE）介导的，例如基因组岛（GI）。GI 中的一个或一组基因通过水平基因转移（HGT）在不同物种之间和内部进行交换。基于 GI 在细菌生存和增殖中可能发挥的关键作用，它们被引入作为与环境和病原体相关的因素。碳酸酐酶 (CA) 参与许多关键的生化途径，例如 pH 动态平衡和电解质转移的调节。在 CA 的六个进化家族中，β-CA 基因序列存在于许多细菌物种中，在进化过程中可以水平转移到原生动物中。这项研究表明了细菌β-CA 基因序列在 GI 中的参与，并表明了它们在进化过程中向原生动物的水平转移。
