Fig. 1.
Expression of 3a in SARS-CoV infected Vero E6 cells, purified virions and transfected cells. (A) 35S metabolically labeled cell lysates or culture supernatants from mocked infected (lanes 1 and 3) or SARS-CoV infected cells (lanes 2 and 4) were subjected to immunoprecipitation with anti-3a polyclonal antibody. The 3a protein(s) or proteins that interacted with 3a were detected in SARS-CoV infected cells (marked by arrowheads, lanes 2 and 4), but not in mocked infect cells. (B) Western blot analysis, using specific anti-3a antibody (top panel), to detect for the expression of 3a in cells lysates obtained from mock infected cells (lane 1), SARS-CoV infected cells (lane 2), and in virions purified from SARS-CoV infected cells (lane 3). Cells transiently transfected with a DNA construct for expressing 3a were harvested at 1 or 2 days post-transfection and subjected to Western blot analysis (lanes 4 and 5). Untransfected Vero E6 was included as negative control (lane 6). The amounts of total cell lysates loaded for each samples were verified by measuring the level of endogenous tubulin (bottom panel). Note that no tubulin was present in the purified virion (lane 3).