miRNAs是一类内源性、主要在转录后水平对基因进行调控的小分子非编码RNA，参与调节几乎所有的生物学过程。大量证据显示病毒使用miRNA操控宿主细胞和病毒的基因表达，从而方便自身感染和增殖。而病毒感染也会影响宿主细胞miRNA的表达。病毒miRNA可主动调节病毒自身基因的表达，如降低毒力，规避宿主防御等。部分感染昆虫的杆状病毒也已证明能编码miRNA，它们在宿主病毒的相互作用，特别是改写宿主防御反应以有助于病毒自身复制感染的过程中发挥着重要作用。本申报课题在我们已有的研究工作基础上，进一步研究分析杆状病毒模式株AcMNPV编码的miRNA在病毒感染过程中的作用，对靶基因的调控模式，成功感染致病的机制和意义。这将有助于深入理解杆状病毒与其宿主之间复杂的交互作用关系。

MicroRNAs (miRNAs) are class of small endogenous (~22-nucleotide) non-coding RNAs (snRNAs) serve unique level of post-transcriptional gene regulation that modulates a range of fundamental cellular processes. Increasing evidence indicates that viruses use miRNAs to manipulate both cellular and viral gene expression to favor infection. Furthermore, viral infection can exert a profound impact on the cellular miRNA expression profile. Emerging evidence reveals that upon infection viruses alter the host transcriptome either by virus-encoded miRNAs or altering the host endogenous miRNAs for their own benefits. The activities of viral miRNAs mainly including autoregulation of viral gene expression, reducing virulence, avoidance of host defenses, and a likely important role in maintaining latent and persistent infections. Several viruses infecting insects have also been shown to encode miRNAs, which play important roles in host-virus interactions, especially subverting host defense responses to assist the replication of viruses. Here, we meant to elucidate how AcMNPV, the model type of baculovirus encoded miRNAs which we have identified influence viral replication and pathogenic potential through their regulation of viral mRNAs or by reshaping cellular gene expression, and try to cast an insight into their diverse roles in the intricacies of host-virus cross-talking.