Fig 2.
The G3A/C8U double mutation modulates the expression of viral RNA species and increases viral protein expression. (A) Primer extension analysis was performed by reverse transcription using two primers specific to the positive (cRNA and mRNA) and negative (vRNA) species in the same tube for each virus (PR8, PB1SP, or PASP) for the indicated segments (M, NA, PB1, PB2, and PA) at 6 and 12 h postinfection. A representative of three independent primer extension experiments is shown. The band corresponding to the mRNA (m) migrates more slowly (upper band of each doublet) due to the presence of the cap compared to the uncapped cRNA (c) species. The vRNA (v) is also indicated for each segment analyzed. (B) Densitometric analysis for the vRNA species of all segments of the representative experiment in panel A as a percentage of wild-type PR8 control is provided. (C) MDCK cells were infected at an MOI of 1 with PR8, PB1SP, or PASP viruses, and viral protein expression was analyzed 4 and 8 h postinfection. As a control, MDCKs were mock infected with phosphate-buffered saline (PBS) supplemented with bovine albumin.