Figure 6.

Expression of the −73bp PCNA promoter (Dsal) driving the human PCNA gene. Experiments were carried out with the transfected human PCNA gene under the control of the −73bp PCNA promoter (Pietrzkowski et al., 1991). The cells were transfected, and mixed populations were then selected and amplified. The cells were made quiescent and subsequently serum-stimulated for 24 hours. Total RNA was extracted and analyzed by Northern blot; the filters were hybridized both to the Ava II-Pst I fragment of the human PCNA cDNA that recognizes only the human PCNA mRNA and to the histone H3 probe. Lane 1, quiescent cells; lane 2, serum-stimulated cells at the permissive temperature; lane 3, serum-stimulated cells at the restrictive temperature.