Associate Professor of Microbiology
All viruses have host-ranges. Some viruses can infect many cell types while others can only infect one or a few cell types. We use baculovirus as a model to elucidate host-range factors of viruses, specifically on cellular secretion upon viral infection.
Baculovirus are insect specific viruses that have potential for biological control of insect pests in agriculture. Most baculoviruses, however, have a very narrow host-range, killing one or two host insects. This is one of the major drawbacks of baculoviruses as pesticides, making them difficult to compete with broad spectrum chemicals. Host-range factor studies of baculovirus will allow us engineer baculoviruses with a particular host-range for insect control in agriculture. Development of baculoviruses with specific host-ranges will offer ecological benefits by reducing chemical insecticide dependence with application of beneficial viruses in agriculture and forestry.
It is unknown why some viruses have a wide host-range whereas others have a very narrow host-range. In baculoviruses, the Autographa californica M NPV (AcMNPV) has a wide host-range (>33 species) and can replicate well in many cell lines. Narrow host-range NPVs, such as Spodoptera exigua M NPV (SeMNPV) and Thysanoplusia orichalcea M NPV (ThorMNPV), can kill only one or a few hosts and replicate well in a few cell lines. ThorMNPV replicates poorly in a cell line Sf21 but AcMNPV replicate in Sf21 very well. We engineered narrow host-range ThorMNPV (vThGFP) and SeMNPV (vSeGFP) with the insertion of green fluorescent protein (GFP) gene for expression as well as AcMNPV (vAcRed) with red fluorescent protein (RFP) for expression in cell. When we co-infected Sf21 cells with vAcRed and vThGFP, vAcGFP helped vThGFP replication by about 100-fold. SeMNPV is poor in infecting Hi5 cells from Trichoplusia ni. Co-infection of Hi5 cells with vAcRed and vSeGFP showed that vAcRed substantially helped vSeGFP replication in Hi5 cells. Centrifuged media from Sf21 and Hi5 cells infected by vAcRed also helped vThGFP and vSeGFP replication in Sf21 and Hi5 cells, respectively. We hypothesized that wide host-range AcMNPV infection in cells can stimulate cells to secrete a factor(s) that can help other narrow host-range viruses to replicate in otherwise nonpermissive cells. We try to search for the factors by using different techniques such as two dimensional gel electrophoresis, a dual fluorescence reporter tag system and recombinant DNA.
In addition to baculovirus, we also study ascovirus. Ascoviruses are also insect specific viruses with different host-ranges among different ascovirus species. Ascovirus looks similar to baculovirus in morphology but they are always found in the cytoplasm of infected cells whereas baculovirus is always found in the nucleus. We are interested in understanding which genes of ascovirus are transcribed by the host cell and which are transcribed by the viral encoded RNA polymerase. We are also interested in understanding if late genes are terminated by stem-loop structure formation, as in bacteria
- Xue, J.-L., and X.-W. Cheng. Using Host 28S Ribosomal RNA as a Housekeeping Gene for Quantitative Real-Time Reverse Transcription-PCR (qRT-PCR) in Virus-Infected Animal Cells. Current Protocols in Microbiology. John Wiley & Son, NJ, USA (in press).
- Xue, J.-L., T.Z. Salem, C.M. Turney, X.-W. Cheng. 2010. Strategy of the use of 28S rRNA as a housekeeping gene in real-time quantitative PCR analysis of gene transcription in insect cells infected by viruses. Journal of Virological Methods 163:210-215.
- Cheng, X.-W. and D.-E. Lynn. 2009. Baculovirus interactions in vitro and in vivo. In Advances in Applied Microbiology Volume 68 pp. 218-239. Edited by A. I. Laskin, G. M. Gadd, and S. Sariaslani. Elsevier Inc. San Diego, California. (invited book chapter)
- Wang, L.-H, T. Z. Salem, D. J. Campbell, C. M. Turney, C. M. S. Kumar and X.-W. Cheng (2009). Characterization of a virion occlusion defective Autographa californica multiple nucleopolyhedrovirus (AcMNPV) mutant lacking the p26, p10 and p74 genes. Journal of General Virology 90: 1641-1648. (Figures on cover page).
- Wang, L.-H., T. Z. Salem, D. E. Lynn and X.-W. Cheng. 2008. Slow cell infection, inefficient primary infection and inability to replicate in fat body determine host-range of Thysanoplusia orichalcea M Nucleopolyhedrovirus (ThorMNPV). Journal of General Virology 89, 1402-1410.
- Salem, T. Z., C. M. Turney, L-H. Wang, J.-L. Xue, X.-F. Wan and X.-W. Cheng. 2008. Transcriptional analysis of a major capsid protein gene from Spodoptera exigua Ascovirus 5a. Archives of Virology 153, 149-162.
- Cheng, X.-W., X.-F. Wan, J.-L. Xue and R. C. Moore. 2007. Ascovirus and its evolution. Virologica Sinica 22, 137-147.
- Wang, L.-H, J.-L Xue, C. P. Craig, B. M. Arif, X.-W. Cheng. 2006. Sequence and organization of the Trichoplusia ni ascovirus 2c (Ascoviridae) Genome. Virology 354, 167-177.
- Cheng, X.-W, L. Wang, G. R. Carner, B. M. Arif. 2005. Characterization of Three Ascovirus Isolates from Cotton Insects. Journal of Invertebrate Pathology 89, 193-202.
- Cheng, X.-W., G.R. Carner, M. Lange, J.A. Jehle, and B.M. Arif. 2005. Biological and Molecular Characterization of a Multicapsid Nucleopolyhedrovirus from Thysanoplusia orichalcea (L.) (Lepidoptera: Noctuidae). Journal of Invertebrate Pathology, 88:126-135.
- Cheng, X.-W., T.R. Henriques, S.R. Coppens, Q. Feng, A. Retnakaran, P.J. Krell, and B.M. Arif. 2003. Strategy to screen long DNA inserts in E. coli. BioTechniques 34:6.
- Cheng, Xiao-Wen, Peter J. Krell and Basil M. Arif 2001. P34.8 (GP37) is not essential for baculovirus replication. Journal of General Virology 82 (2), 299-305.
- Cheng, Xiao-Wen and Gerald R. Carner 2000. Characterization of a single-nucleocapsid nucleopolyhedrovirus of Thysanoplusia orichalcea L. (Lepidoptera:Noctuidae) from Indonesia. Journal of Invertebrate Pathology 75, 279-287.
- Cheng, Xiao-Wen, Gerald R. Carner and Basil M. Arif 2000. A new ascovirus from Spodoptera exigua and its relatedness to the isolate from Spodoptera frugiperda. Journal of General Virology 81, 3083-3092.
- Cheng, Xiao-Wen, Gerald R. Carner and Thomas M, Brown 1999. Circular configuration of the genome of ascoviruses. Journal of General Virology 80, 1537-1549.
- Cheng, Xiao-Wen, Gerald R. Carner and Howard W. Fescemyer 1998. Polyhedrin sequence determines the tetrahedral shape of occlusion bodies in Thysanoplusia orichalcea single-nucleocapsid nucleopolyhedrovirus. Journal of General Virology 79, 2549-2556.