Mechanistically , Sag deletion caused accumulation of Jun-B , a substrate of Sag-Fbxw7 E3 ligase and a transcription factor that drives p16 transcription .
O O B-GeneOrGeneProduct O O O O B-GeneOrGeneProduct O O O O I-GeneOrGeneProduct B-GeneOrGeneProduct I-GeneOrGeneProduct O O O O O O B-GeneOrGeneProduct O O