Mutational analysis of the SDD sequence motif of a PRRSV RNA-dependent RNA polymerase

Zhou, Yan; Zheng, HaiHong; Gao, Fei; Tian, DeBin; Yuan, ShiShan

BHK-21 cells transfected with full-length mutant plasmid and pAPRRS were grown on a 6-well plate at 37°C. Indirect IFAs were carried out by standard procedures [29] , using a 1 : 600 dilution of a PRRSV monoclonal antibody directed against the PRRSV open reading frame 7 (ORF7, encoding a nucleocapsid protein), and antibody anti-PRRSV nsp2 (kindly provided by Dr. Fang Ying at South Dakota State University) (Figure 3 ). After three washes with PBS, cells were incubated at 37°C for 1 h with goat anti mouse secondary antibody Alexa Fluor® Dyes (Invitrogen, Carlsbad, CA, USA). The samples were examined with an Olympus fluorescence microscope equipped with a digital camera and Qfluoro software (Leica).