Interleukin 2-induced expression of proliferating cell nuclear antigen is regulated by transcriptional and post-transcriptional mechanisms.

Proliferating cell nuclear antigen (PCNA) is an auxiliary protein required for leading strand DNA synthesis by polymerase delta. Steady-state levels of PCNA RNA increase during interleukin 2 stimulated G1 activation of cloned T cells (L2 cells) and correlate with expression of the PCNA protein. We demonstrate that the initial (G1) rapid rise in PCNA RNA levels is predominantly related to increased transcription. The slower rate of increase in PCNA RNA at the initial G1-S transition is related to transcription as well as increased stability of the PCNA message and partially requires protein synthesis. These data provide a foundation for further investigation of the mechanisms of increased stability and transcription of PCNA.