|Pringle, Fiona - UNIV OF ALABAMA|
|Johnson, Karyn - UNIV OF ALABAMA|
|Ball, Andrew - UNIV OF ALABAMA|
Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 3, 2002
Publication Date: March 19, 2003
Citation: PRINGLE, F.M., JOHNSON, K.N., GOODMAN, C.L., MCINTOSH, A.H., BALL, A.L. PROVIDENCE VIRUS: A NEW MEMBER OF THE TETRAVIRIDAE THAT INFECTS CULTURED INSECT CELLS. VIROLOGY. 2003. V. 306. P. 359-370. Interpretive Summary: The problem that needed to be resolved in this research was to determine whether a virus found growing in an insect cell line was a new virus and thus not previously classified. Insect cell culture is the term used to describe the growth of cells, taken from various tissues, in culture flasks containing a sterile liquid food source called a growth medium. In the course of establishing such cultures called cell lines, we found that cells taken from the gut of an economically important pest of crops called the corn earworm, and grown in culture, contained an insect virus. The virus was identified as belonging to a group of viruses, called 'tetraviruses,' that have been shown to be effective biological control agents of insect pests, and this new virus may possess such potential. This finding could therefore benefit farmers, the agricultural industry and scientists. In addition this is the first report of this type of virus being successfully grown in insect cells in culture.
Technical Abstract: We identified a new member of the Tetraviridae, Providence virus (PrV), persistently infecting a cell line derived from the midgut of Helicoverpa zea (corn earworm). Virus purified from these cells also productively infected a H. zea fat body cell line and a cell line from whole embryos of the beet armyworm, Spodoptera exigua. PrV is thus the first tetravirus shown to replicate in cell culture. PrV virions are isometric T = 4 particles composed of two structural proteins (60 and 7.4 kDa) that encapsidate both the viral RNA genome (6.4 kb) and a subgenomic RNA (2.5 kb). The monopartite organization of the PrV genome resembles that of Nudaurelia ß virus and Thosea asigna virus, members of the genus Betatetravirus. The infectivity of PrV for cultured cells uniquely permitted examination of tetravirus RNA and protein synthesis during synchronous infection. The discovery of PrV greatly facilitates studies of tetravirus molecular biology.