Figure 4.
ATF binding site in the TSRE is temperature sensitive and important for cyclin A transcription. Reporter constructs containing either no TSRE (vector), wild-type (TSRE), or a mutant TSRE in which sequences adjacent to (mCtrl–TSRE) or within the ATF site (mATF–TSRE) have been changed upstream of the TdT initiator were transfected into ts13 cells maintained at either 33.5°C or 39.5°C. The relative transcriptional activity of each promoter was determined as described in Materials and Methods. The sequence of the wild-type and mutant DNA fragments is given in Fig. 5C.