Department of Agricultural Biotechnology, College of Agriculture and Life Science, Seoul National University, Seoul, Korea.
PLoS One. 2012;7(7):e42462. doi: 10.1371/journal.pone.0042462. Epub 2012 Jul 31.
The impact of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) infection on host gene expression in Spodoptera exigua 4th instar larvae was investigated through the use of 454 sequencing-based RNA-seq of cDNA libraries developed from insects challenged with active AcMNPV or heat-inactivated AcMNPV.
METHODOLOGY/PRINCIPAL FINDINGS: By comparing the two cDNA libraries, we show that 201 host genes are significantly up-regulated and 234 genes are significantly down-regulated by active AcMNPV infection. Down-regulated host genes included genes encoding antimicrobial peptides, namely three gloverin isoforms and an attacin, indicating that the viral infection actively repressed the expression of a portion of the host immune gene repertoire. Another interesting group of down-regulated host genes included genes encoding two juvenile hormone binding proteins and a hexamerin, all of which are involved in juvenile hormone regulation. The expression of these genes was enhanced by the topical application of Juvenile Hormone III (JHIII) in the insects challenged with heat-inactivated AcMNPV. However, infection with the active virus strongly suppresses the expression of these three genes, regardless of the absence or presence of JHIII.
CONCLUSIONS/SIGNIFICANCE: Using RNA-seq, we have identified groups of immune-regulated and juvenile hormone-regulated genes that are suppressed by infection with active AcMNPV. This information and further studies on the regulation of host gene expression by AcMNPV will provide the tools needed to enhance the utility of the virus as an effective protein expression system and as an insecticide.
通过使用基于 454 测序的 cDNA 文库的 RNA-seq 对感染活跃的 Autographa californica 多粒核型多角体病毒（AcMNPV）或热失活的 AcMNPV 的昆虫进行挑战，研究了 AcMNPV 感染对斜纹夜蛾 4 龄幼虫宿主基因表达的影响。
方法/主要发现：通过比较这两个 cDNA 文库，我们表明，201 个宿主基因被活跃的 AcMNPV 感染显著上调，234 个基因显著下调。下调的宿主基因包括编码抗菌肽的基因，即三种 gloverin 同工型和一种 attacin，表明病毒感染积极抑制了一部分宿主免疫基因库的表达。另一组下调的宿主基因包括编码两种保幼激素结合蛋白和一种 hexamerin 的基因，所有这些基因都参与保幼激素的调节。在昆虫中用保幼激素 III（JHIII）进行局部处理，挑战热失活的 AcMNPV 时，这些基因的表达增强。然而，感染活跃的病毒会强烈抑制这三个基因的表达，无论是否存在 JHIII。
结论/意义：使用 RNA-seq，我们已经鉴定了一组受感染的免疫调节和保幼激素调节基因，这些基因受到活跃的 AcMNPV 感染的抑制。这些信息和对 AcMNPV 宿主基因表达调控的进一步研究将提供所需的工具，以增强病毒作为有效蛋白表达系统和杀虫剂的效用。
