TABLE 2.

RNA synthesis properties of the nsP2 PI mutants

VirusnsP2 lesion26 RNA:genomeMinus-strand synthesisP123/P23 accumulation% wt RNA synthesisRC+ssRNA:RF (cpm)
RatioFoldContinuousRelative rateTurnoverRate/h
SIN wtwt17:1a1.0100%NDc13:1
SIN S1A1>E13:1a0.8++5+20:1
SFV 2AL10>T2.7:1a1.4++3+17%40:1
SFV wtwt2:1a1.0ND
SFV 1BD469Δ0.8:1a0.4++4+13%15:1
SFV 2CL713>P5.9:1a3.0+2+13%100:1
SIN S2P726>T21:1a1.2+2+125:1
SIN rep wtwt2.7:1b1.04510:1
RNase L−/−wt nsP2wt1.0+ND10 (CEF)+16%
Aedes C7/10wt nsP2NDND+ND2+22%
  • a Values are molar ratios, obtained from Perri et al. (39), and represent accumulated RNA from a 7-h continuous-labeling period.

  • b Values are molar ratios and represent the incorporation (averages from 4 to 5 h p.i. and 6 to 7 h p.i. lysates) in 1-h pulse-labeling periods by BHK21 cells infected with packaged wt SIN replicons. The areas of a 0.8% TBE-agarose gel containing the viral RI/native RF, or 49S or 26S mRNA were identified by fluorography and were cut out and their cpm determined by counting in a Beckman LS-335 scintillation counter. For molar ratios, the incorporation value in 49S genome RNA was divided by a factor of 2.8, the size difference between the 49S genome and 26S subgenomic RNA, and this value was divided by the incorporation value in 26S mRNA.

  • c ND, not done.