Promoter activity. The probability of transcription from both promoters, Cp (blue) and Qp (red) as function of EBNA-1 and Oct-2 proteins in the system. This plot shows the case when Oct-2+Grg/TLE has the maximum binding affinity to FR, K
= 2.5 nM. The Qp activity is remarkably low for most EBNA-1 levels compared with the Cp activity.