Research

Morphogenesis of the auditory organ in mammals

Nicolas Thelen, Marc Thiry

The organ of hearing in mammals is undoubtedly one of the most remarkable structures encountered in higher vertebrates. It is composed of alternating sensory cells and supporting cells. At the mature, this highly ordered structure is well described, but many question marks persist about its formation. We are trying to understand how and when the auditory organ sets up, and what are the factors involved in the developmental control. The value of this work is especially important because there is until now no possibility to regenerate sensory cells in mammal adults.

Structure-function organization of the nucleolus in eukaryotic cells

Marc Thiry

The nucleolus is the main site of ribosome formation. It is not only the site of 18S, 5.8S and 28S ribosomal RNA synthesis but is also the site of their maturation and their assembly with, on the one hand, 5S ribosomal RNA and with, on the other hand, proteins of cytoplasmic origin, creating macromolecular buildings called preribosomic particles. In addition to the ribosome biogenesis, the nucleolus is involved in other functions such as the formation of various ribonucleoproteinic molecules. The nucleolus is a highly organized structure, which consists of 2 or 3 distinct compartments according to the species considered. Our project is trying to better understand the relationships between the various components and functions of the nucleolus. Why does in eukaryotes a third nucleolar compartment appear in amniotes? Could the bipartite nucleoli be at the origin of the tripartite nucleoli during the evolution of species? Could the subdivision of nucleoli in 2 or 3 constituents be directly linked to the structure of ribosomal genes? Is the formation of the different ribonucleoproteinic molecules linked to the ribosome biogenesis?