The interactions between Emiliania huxleyi and E. huxleyi virus (EhV) regulate marine carbon and sulfur biogeochemical cycle and play a prominent role in global climate change. As a large DNA virus, EhVs have developed a novel "virocell metabolism" model to meet their higher metabolic needs. However, the regulatory mechanism of this metabolic model is still largely unclear. MicroRNAs (miRNAs) can regulate biological pathways through targeting hub genes in the metabolic processes. Here, we performed high-throughput small RNA sequencing to analyse miRNA expression in EhV99B1 infected E. huxleyi BOF92. A total of 26 miRNAs (including 2 virus-derived miRNAs) were identified, including four up-regulated and one down-regulated miRNAs. These results were further validated through quantitative real-time PCR. Functional enrichment analysis showed that five differentially-expressed miRNAs might be involved in the regulation of carbohydrate metabolism, lipid metabolism and amino acid metabolism. Moreover, the expression levels of differentially-expressed miRNAs were negatively correlated with that of several lipid metabolism-related genes, such as ACC-1, SPT, ACOX, ACAT, CERS and ACADS, indicating that these miRNAs might play an important regulatory role in virus-mediated lipid metabolism.
海洋颗石藻病毒-宿主互作是影响海洋碳、硫生物地化循环及全球气候变化的重要环节。作为大的双链DNA病毒,颗石藻病毒进化出一种“病毒细胞代谢”模式,通过重编程宿主代谢途径以满足其代谢需求,但对这一代谢模式的调控机制尚缺乏足够的认识。MicroRNA (miRNA)作为一种基因表达调控的重要因子,能够通过调控代谢过程中的靶基因表达,从而调节相关代谢通路。本研究采用small RNA测序技术分析病毒感染颗石藻差异表达的miRNA及其靶基因功能,鉴定出26条成熟miRNA (包括2条病毒来源的miRNA),均来自23条新的miRNA前体序列,其中5条miRNA显著差异表达,包括4条上调,1条下调。实时荧光定量PCR (quantitative real-time PCR, qRT-PCR)验证结果与miRNA-seq结果基本一致。功能富集分析显示,5个差异表达的miRNA可能参与调节糖代谢、脂代谢和氨基酸等代谢。此外,差异表达miRNA的表达水平与脂质代谢相关靶基因如ACC-1、SPT、ACOX、ACAT、CERS、ACADS等的表达水平呈负相关,说明这些miRNA可能在病毒感染过程中对宿主的脂质代谢发挥重要的调控作用。.
Keywords: Emiliania huxleyi virus; Emiliania huxleyi; lipid metabolism; microRNA; small RNA sequencing.