Masoumi, AmirHanzlik, TerryChristian, Peter D2015-12-132015-12-130168-1702http://hdl.handle.net/1885/75318Cricket paralysis virus (Dicistroviridae: Cripavirus) (CrPV) naturally has a wide range of insect hosts which is reflected in its ability to infect several cultured insect cell lines. The expression of viral gene products is controlled by two kinds of internal ribosome entry site (IRES) elements, 5′ and intergenic (IG). Using seven cultured cell lines we tested the functionality of both IRES elements by transfection with bi-cistronic RNA constructs. In six of the seven cell lines, expression initiated from both IRES's was significantly higher than that from a control construct and in five of these six lines the expression from the 5′-IRES was higher than that from the IG-IRES. Permissiveness of each of the cell lines for replication of CrPV was tested by infection with purified virions and transfection with viral RNA. Only three of the cell lines were fully permissive for CrPV replication and no correlation between permissiveness and IRES activity was apparent. These results suggest that while IRES function is required for permissiveness, additional cellular and/or viral factors, involved in processing of viral products, packaging of viral particles and interacting with the cap-dependent translation machinery of host cells, are necessary for CrPV to be able to replicate in any given cell.Keywords: luciferase; recombinant protein; spacer DNA; 5' untranslated region; animal; article; cell line; genetic transfection; genetics; growth, development and aging; insect virus; metabolism; physiology; protein synthesis; regulatory RNA sequence; reporter gene Cell culture; CrPV; Dicistrovirus; IRES; Transfection; Virus replication200310.1016/S0168-1702(03)00139-42015-12-11