Time-lapse imaging of nuclear bodies.

Fluorescence microscopy is a powerful technique that has become central in the study of the structure and function of biological specimens. This is due in large part to its specificity and versatility. Although an understanding of structure-typically through high-resolution imaging of fixed material-has proved an important tool to understanding function, fluorescence microscopy also offers a mechanism to interrogate cells in the living state, providing a means to explore dynamic process within the specimen over long time periods at high temporal resolution. The cell nucleus is a highly compartmented environment whose components are often highly motile and in a constant state of flux. The ability to monitor the dynamic behavior of nuclear bodies by live-cell imaging provides the researcher with important information regarding underlying mechanistic processes relating to their formation and maintenance. Two techniques have proved particularly valuable to our study of cellular dynamics and molecular mobility, namely, time-lapse imaging and fluorescence recovery after photobleaching (FRAP). Time-lapse microscopy allows for qualitative and quantitative analysis of a wide range of events at the cellular and subcellular level. FRAP provides a mechanism to study the mobility of a population of proteins in a range of conditions within discrete areas of the biological specimen. Therefore, fluorescence microscopy is unique in its ability to provide data at high temporal resolution and in such exquisite detail.