Dr. Johnson studies transcriptional responses to oncogenic Ras signaling, seeking to understand the pathways that regulate oncogene-induced senescence and how this intrinsic tumor suppression mechanism is bypassed in cancer cells. His laboratory focuses on the transcription factor C/EBPbeta, which is post-translationally activated by Ras signaling and has both pro- and anti-oncogenic activities. His group has identified a novel regulatory mechanism by which the Cebpb mRNA 3' untranslated region suppresses Ras-induced activation of C/EBPbeta and thus facilitates senescence bypass in tumor cells. The 3'UTR effect involves mRNA localization and compartmentalization of Ras effector kinases.