Structure and function in the nucleus: subnuclear trafficking of DNA replication factors.

The traditional view of the eukaryotic cell nucleus as a more or less amorphous milieu in which proteins and nucleic acids are freely floating has been challenged by an ever increasing number of reports uncovering highly organized structures where biological processes are concentrated together with their corresponding factors. The identification and utilization of protein domains that are necessary and sufficient for targeting to different subnuclear compartments have begun to elucidate the molecular principles underlying this structural organization and its dynamic behavior. The combination of biochemical, cell biology, and biophysical approaches to study nuclear structure and function should help to elucidate how these higher-order structures organize and coordinate countless enzymatic activities in time and space within the mammalian nucleus. J. Cell Biochem. Suppls. 32/33:15-23, 1999. Copyright 1999 Wiley-Liss, Inc.