Elsevier Inc. ribosome biogenesis pathway rRNA maturation pathway pre-rRNA transcript Sirt1 Sirt7 Sirt7 --+> RNA polymerase I normal conditions --+> RNA polymerase I Ncl ---> pre-rRNA transcript Crebbp ---| RNA polymerase I nucleolar stress --+> p53 signaling pathway nutrients stress conditions stress conditions ---| SL1 complex Sirt1 ---| SL1 complex stress conditions ---| Sirt7 stress conditions --+> adenosine monophosphate-activated protein kinase (AMPK) signaling pathway nutrients --+> mTOR signaling pathway nutrients --+> the extracellular signal-regulated Raf/Mek/Erk signaling pathway adenosine monophosphate-activated protein kinase (AMPK) signaling pathway ---| SL1 complex mTOR signaling pathway --+> SL1 complex the extracellular signal-regulated Raf/Mek/Erk signaling pathway --+> SL1 complex Ncl ---> ribosome biogenesis pathway Ncl ---> rRNA maturation pathway RNA polymerase I mTOR signaling pathway FACT complex Ncl chromatin modification/remodeling pathway Ptrf Ttf1 Supt4h1 Supt5h Crebbp Rrn3 Ubtf P- P+ SL1 complex Paf1 complex nucleolar stress Rrn3 ---- SL1 complex SL1 complex ---- Ubtf normal conditions RNA polymerase I ---> pre-rRNA transcript RNA polymerase I ---- Supt5h RNA polymerase I ---- Rrn3 Ptrf ---- Ttf1 Paf1 complex ---- Supt4h1 Paf1 complex ---- Supt5h Supt4h1 ---- Supt5h Supt5h ---> pre-rRNA transcript chromatin modification/remodeling pathway ---> pre-rRNA transcript FACT complex ---> pre-rRNA transcript p53 signaling pathway adenosine monophosphate-activated protein kinase (AMPK) signaling pathway the extracellular signal-regulated Raf/Mek/Erk signaling pathway