DAO 73:89-101 (2006)  -  doi:10.3354/dao073089

Ultrastructure of the replication site in Taura syndrome virus (TSV)-infected cells

Thinnarat Srisuvan1,2,*, Carlos R. Pantoja2, Rita M. Redman2, Donald V. Lightner2

1Department of Livestock Development, 69/1 Phayathai Road, Bangkok 10400, Thailand
2Department of Veterinary Science and Microbiology, University of Arizona, 1117 E. Lowell, Tucson, Arizona 85721, USA

ABSTRACT: Taura syndrome virus (TSV) is a member of the family Dicistroviridae that infects Pacific white shrimp Litopenaeus vannamei (also called Penaeus vannamei), and its replication strategy is largely unknown. To identify the viral replication site within infected shrimp cells, the viral RNA was located in correlation with virus-induced membrane rearrangement. Ultrastructural changes in the infected cells, analyzed by transmission electron microscopy (TEM), included the induction and proliferation of intracellular vesicle-like membranes, while the intracytoplasmic inclusion bodies and pyknotic nuclei indicative of TSV infection were frequently seen. TSV plus-strand RNA, localized by electron microscopic in situ hybridization (EM-ISH) using TSV-specific cDNA probes, was found to be associated with the membranous structures. Moreover, TSV particles were observed in infected cells by TEM, and following EM-ISH, they were also seen in close association with the proliferating membranes. Taken together, our results suggest that the membranous vesicle-like structures carry the TSV RNA replication complex and that they are the site of nascent viral RNA synthesis. Further investigations on cellular origins and biochemical compositions of these membranous structures will elucidate the morphogenesis and propagation strategy of TSV.


KEY WORDS: Taura syndrome virus · TSV · In situ hybridization · Transmission electron microscopy · Litopenaeus vannamei


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