Figure 1

Expression and purification of RVFV nucleoprotein (N) protein. Insect Sf9 cells were infected with a recombinant baculovirus expressing RVFV N protein and four days after infection the expression of N was assessed. A) Infected cell lysate expressing N protein was analyzed by SDS-PAGE followed by Commassie Brilliant blue staining (lane 2) or Western blotting (lane 4) and compared with total proteins from uninfected insect cells (lanes 1 & 3). Protein markers were included and sizes in kilo-Dalton (kDa) are shown at the right. B) Purification of N protein by gel filtration. The position of the peak correspondent to N and the relative elution position of molecular markers are indicated. C) Samples of the gel filtration fractions corresponding to the peak of protein were analyzed by SDS-PAGE and stained with Commassie brilliant blue (lanes 2 to 9). An aliquot of a fraction, prior to N protein fraction, was included as a control (lane1). The relative position of molecular marker is indicated in KDa. D) Purified N protein was analyzed by SDS-PAGE followed by Commassie Brilliant blue staining (lane 2) or Western blotting (lane 3) and compared with total proteins from infected insect cells (lane 1). Protein markers were included (lane M) and sizes in KDa are shown at the right. E) An aliquot of purified N protein were negatively stained with 3% phosphotungstic acid (PTA), pH 6.8 and visualized by electron microscopy. A particulate structure is indicated with an arrow in upper panel and lower panel shows amplified particles. Bar represents 100 nm.