Figure 1.
Transcriptional defect in ts13 cells is promoter specific. Reporter constructs containing the indicated cellular promoter upstream of the luciferase or chloramphenicol acetyltransferase (CAT) gene were cotransfected with a β-galactosidase expression vector into ts13 (A) and ts13R3 (B) cells maintained at 33.5°C (solid bars) or 39.5°C (hatched bars). Between 40 and 48 hr post-transfection, luciferase or CAT activity was measured and normalized for β-galactosidase activity. The transcriptional activity of each promoter at 39.5°C is expressed as a percentage of the activity detected at 33.5°C (given a value of 100%) in the same cell line. The relative activity of each promoter at 33.5°C with respect to cyclin A (given a value of 100) is also shown above each bar. The data represent results observed in three independent transfection experiments, each performed in duplicate.