Antinuclear autoantibodies: fluorescent highlights on structure and function in the nucleus

The eukaryotic nucleus is dynamically organized with respect to particular activities, such as RNA transcription, RNA processing or DNA replication. The spatial separation of metabolic activities is best reflected by the identification of functionally related proteins, in particular substructures of the nucleus. In a variety of human diseases, the integrity of such structures can be compromised, thus underlining the importance of a proper nuclear architecture for cell viability. Besides their clinical relevance, antinuclear autoantibodies (ANAs) have contributed to a large extent to the identification of subnuclear compartments, the isolation and cloning of their components (the autoantigens), as well a the characterization of their function. Although sophisticated techniques, such as confocal laser scanning microscopy (CLSM), fluorescence resonance energy transfer (FRET) and in vivo observation of cellular events have recently been established as valuable tools to study subnuclear architecture and function, cell biologists will continue to appreciate the specificity and power of ANAs for their research.