Regulators of nucleolar functions.

The nucleolus is the ribosome factory and also a multifunctional domain that plays an important role in nuclear organization and function. Interestingly, ribosome biogenesis appears directly related to cell growth and proliferation. The nucleolus corresponds to a very dynamic nuclear domain resulting from an equilibrium between the level of ribosomal RNA synthesis and the efficiency of ribosomal RNA processing. Ribosome biogenesis is regulated throughout interphase and stops during mitosis. The mitotic silencing of transcription, the distribution of the processing machinery, as well as the link between transcription and processing were found to be dependent on cyclin-dependent kinase(s).