Nucleolus: A Central Hub for Nuclear Functions

International audience; The nucleus contains distinct nuclear bodies (NBs); nucleolus is the largest and the most studied NB, but its role in the functioning of the nucleus is far from being fully understood. The nucleolus is not surrounded by a membrane, yet it contains DNA, RNA and a set of proteins that can either be retained in the nucleolus or rapidly shuttle between the nucleoplasm, the nucleolus and the cytoplasm in response to various stimuli. The emerging evidence points to the central function of the nucleolus in organizing many nuclear functions besides RNA polymerase I transcription and ribosome biogenesis. Here we discuss the functions of the nucleolus related to the shuttling of proteins and nucleic acids between nucleolus and nucleoplasm. The functional processes affected by shuttling of nucleolar components include 3D organization of the genome, stress response, DNA repair and recombination, transcription regulation, telomere maintenance and other essential cellular functions.