ARS | Publication request: Suppression of AcMNPV replication by adf and thymosin protein up-regulation in a new testis cell line, Ha-shl-t

Submitted to: Archives of Insect Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 1, 2012
Publication Date: January 11, 2013
Citation: Zhang, X., Chen, M., Ma, X., Zhao, X., Wang, J., Song, Q., Stanley, D.W., Shao, H. 2013. Suppression of AcMNPV replication by adf and thymosin protein up-regulation in a new testis cell line, Ha-shl-t. Archives of Insect Biochemistry and Physiology. 82(3):158-171.

Interpretive Summary: Long-term agricultural sustainability is severely threatened by widespread use of classical insecticides. Threats include increasing resistance to insecticides and sharply decreasing environmental quality. The concept of biological control of insects is a potentially powerful alternative to classical insecticides. Biological control is based on the idea that direct application of certain insect-specific predators, pathogens and parasites can reduce pest insect populations to a point that the pests exert only negligible economic damage. A major problem, however, is that the most effective pathogenic insect viruses have a very narrow range of hosts. This limits the usefulness of any given virus in biological control programs. In this paper, we examined the relationship between an insect pathogenic virus and its host, an insect cell line. We learned that the host cells suppress viral replication by up-regulating two specific genes that act in cell function. This is a novel finding that scientists who study insect/pathogenic virus relationships will use in research designed to understand how viruses can be manipulated to broaden their host range. Ultimately, this research will benefit crop producers and the people who depend on the crops.

Technical Abstract: Host cytoskeletons facilitate the entry, replication and egress of viruses; because cytoskeletons are essential for viral survival, one mechanism of resisting viral infections involves regulating cytoskeletal polymerization/depolymerization. However, the molecular mechanisms of regulating these changes in cytoskeleton to suppress viral replication remain unclear. We established a cell line (named Ha-shl-t) from the pupal testis of Helicoverpa armigera (Lepidoptera: Noctuidae). The new testis cell line suppresses Autographa californica multiple nucleocapsid nucleopolyhedrovirus (AcMNPV) replication via disassembly of cytoskeleton. Up-regulation of thymosin (actin disassembling factor) and adf (actin depolymerizing factor) reduces F-actin. Silencing thymosin or adf or treating cells with the F-actin stabilizer phalloidin led to increased AcMNPV replication, while treating cells with an F-actin assembly inhibitor Cytochalasin B decreased viral replication. We infer that Ha-shl-t cells utilize F-actin depolymerization to suppress AcMNPV replication by up-regulating thymosin and adf. We propose Ha-shl-t as a model system for investigating cytoskeletal regulation in antiviral action and testicular biology generally.