Where do we go in the nucleus?

The nucleus contains the genetic patrimony of the cell, protects it against environmental stress, and ensures its repair, and its duplication and transcription. The nucleus is limited by a well-defined nuclear envelope. In contrast to cytoplasmic compartments, membranes do not limit nuclear compartments. However, after four decades of extensive investigations, many nuclear domains have been morphologically defined and some have been functionally characterized. The best example is the nucleolus, which is responsible for rRNA synthesis and the assembly of ribosomal subunits. The relationships between the structure of the nucleolus and its functions have been relatively well established. As to nucleoplasmic compartments, many have been morphologically characterized, but their functions are often only partially understood or are still elusive. This includes a variety of nuclear bodies, which are often characterized by the presence of specific proteins, but their role in nuclear functions still remains to be revealed.