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.