Navarro-Domínguez Beatriz, Martín-Peciña María, Ruiz-Ruano Francisco J, Cabrero Josefa, Corral José María, López-León María Dolores, Sharbel Timothy F, Camacho Juan Pedro M
Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva s/n, 18071, Granada, Spain.
Department of Biology, University of Rochester, Rochester, NY, 14627, USA.
Chromosoma. 2019 Mar;128(1):53-67. doi: 10.1007/s00412-018-00689-y. Epub 2019 Jan 7.
Parasitism evokes adaptive physiological changes in the host, many of which take place through gene expression changes. This response can be more or less local, depending on the organ or tissue affected by the parasite, or else systemic when the parasite affects the entire host body. The most extreme of the latter cases is intragenomic parasitism, where the parasite is present in all host nuclei as any other genomic element. Here, we show the molecular crosstalk between a parasitic chromosome (also named B chromosome) and the host genome, manifested through gene expression changes. The transcriptome analysis of 0B and 1B females of the grasshopper Eyprepocnemis plorans, validated by a microarray experiment performed on four B-lacking and five B-carrying females, revealed changes in gene expression for 188 unigenes being consistent in both experiments. Once discarded B-derived transcripts, there were 46 differentially expressed genes (30 up- and 16 downregulated) related with the adaptation of the host genome to the presence of the parasitic chromosome. Interestingly, the functions of these genes could explain some of the most important effects of B chromosomes, such as nucleotypic effects derived from the additional DNA they represent, chemical defense and detoxification, protein modification and response to stress, ovary function, and regulation of gene expression. Collectively, these changes uncover an intimate host-parasite interaction between A and B chromosomes during crucial steps of gene expression and protein function.
寄生会引发宿主适应性的生理变化，其中许多变化是通过基因表达的改变来实现的。这种反应或多或少具有局部性，具体取决于受寄生虫影响的器官或组织；若寄生虫影响整个宿主体，则会引发全身性反应。后一种情况中最极端的是基因组内寄生，即寄生虫作为任何其他基因组元件存在于宿主的所有细胞核中。在此，我们展示了寄生染色体（也称为B染色体）与宿主基因组之间的分子相互作用，这种相互作用通过基因表达的变化得以体现。对草蜢Eyprepocnemis plorans的0B和1B雌性个体进行转录组分析，并通过对4只不含B染色体和5只携带B染色体的雌性个体进行微阵列实验验证，结果显示两个实验中188个单基因的基因表达均发生了变化。一旦排除源自B染色体的转录本，有46个差异表达基因（30个上调和16个下调）与宿主基因组对寄生染色体存在的适应性相关。有趣的是，这些基因的功能可以解释B染色体的一些最重要的影响，例如它们所代表的额外DNA产生的核型效应、化学防御和解毒、蛋白质修饰和应激反应、卵巢功能以及基因表达调控。总体而言，这些变化揭示了在基因表达和蛋白质功能的关键步骤中，A染色体与B染色体之间存在密切的宿主 - 寄生虫相互作用。
