The PML nuclear bodies: actors or extras?

The PML and SP100-containing nuclear bodies (NBs) represent the best-studie d example of a defined nuclear substructure the integrity of which is compr omised in certain human diseases, including leukemia, neurodegenerative dis orders and viral infection. Although recent progress has underscored the un expectedly broad involvement of NE constituents in the control of cell grow th, gene regulation and apoptosis in both pathological and normal contexts, evidence for a specific physiological activity within the NBs remains scan t, thus precluding a unifying hypothesis for NE function.