Human nucleolar RNA pol I interacting proteins identified by immuno-precipitation and mass spectrometry

Ribosome biogenesis is a highly regulated multistep process that controls cell growth and proliferation. The first and key regulatory step of ribosome biogenesis is represented by the transcription of ribosomal RNA (rRNA) genes by RNA polymerase (pol) I in the nucleolus. Activity of RNA pol I is tightly regulated by interactions with many auxiliary factors that mediate promoter recognition and contribute to transcription initiation, elongation and termination. In this study we were able to identify by mass spectrometry some of the known components of the RNA pol I transcribing machinery, and at the same time we identify some novel interactors.