[Chromatin structure and gene regulation].

It is becoming increasingly clear that the nucleosome, the basic repeat unit of eukaryotic chromatin, is involved also in gene regulation. In particular, the study of inducible genes has shown that nucleosomes contribute to the repressed basal state, and that they can be rearranged in response to induction. The role of the nucleosomes in gene regulation and possible mechanisms for their structural modulation are discussed.