The nucleolus through the years

At present it is clear that nucleoli are multifunctional cell organelles and participate in the cell proliferation, resting state, differentiation, maturation, aging and death. Therefore, they also represent very useful morphological markers of these cell states under physiological, pathological and experimental conditions. One of important nucleolar functions related to the mentioned cell states represents the transcription of ribosomal RNA and assembly of pre-ribosomal particles. Thus nucleoli participate in the creation of the cytoplasmic translation machinery necessary for the cell life and function. Although main nucleolar functions are already known, some of recently reported new additional functions depend on the role of a variety of nucleolar proteins some of which are not participating in the ribosomal biogenesis. It is natural that the role of newly discovered nucleolar proteins is still under discussions and remains to be clarified depending on new methodical approaches. It should be also mentioned that the visualization of some of these proteins and nucleolar localization also are and will be a subject for further studies.