Figure 5.

Transcriptional activity of the different constructs measured by run-on assay. The experiments were performed as described in Materials and Methods. The cells were made quiescent (lane 1), then serum-stimulated for 20 hours at either the permissive temperature (lane 2) or the restrictive temperature (lane 3). A. Cells transfected with the human PCNA gene with its own flanking sequences. B. Cells transfected with the human PCNA gene under the control of the SV40 promoter and with the SV40 polyadenylation signal. The amount of DNA/slot was 1 μg. The probes used were the Nru I-Pst I fragment of the exon 1 of the human PCNA gene, the EcoR V-EcoR I fragment containing both exon 2 and 3 of the PCNA gene, the λ DNA and the β-actin DNA (see Materials and Methods).