Table 1.

Effect of CA150 on basal transcription from different viral promotersa

CA150Reporter plasmidCAT activitybLUC activitycCorrected CAT activitydFold inhibition
Absente HIV-CAT675.25,995675.2
CMV-IE-CAT323.24,375323.2
SV40-CAT802.75,053802.7
RSV-CAT463.23,185463.2
PresentHIV-CAT151.36,385142.74.7
CMV-IE-CAT238.03,590285.61.1
SV40-CAT533.75,704485.11.6
RSV-CAT746.45,309466.51.0
  • a Cells were cotransfected with 0.1 μg of the reporter plasmids HIV-CAT, SV40-CAT, and RSV-CAT, or with 0.01 μg of CMV-IE-CAT, in the presence of 3 μg of the CA150-expressing construct. Transfection and activity assays were done as described in Materials and Methods. All results shown are the averages of data from duplicate specimens in a representative experiment. Transfections and activity assays were performed at least three times for each plasmid with similar results.

  • b CAT activity is the value of the slope of the linear function obtained by plotting counts per minute of acetylated chloramphenicol versus time (41).

  • c Luciferase (LUC) activity was obtained by measuring light emission in the same samples with a luminometer. Values are per microgram of cell extract. The HSV TK promoter was driving luciferase expression. Cells were cotransfected with 0.01 μg of this plasmid in the presence of the indicated constructs.

  • d Corrected CAT activities are normalized to luciferase activity.

  • e Empty vector was used to balance the promoter concentration.