Seeking Common Ground in Nuclear Complexity

On a molecular scale, the nucleus is a big place. And, due to the enormous mass of DNA, RNA, and protein concentrated there, the nucleus is far denser than the cytoplasm. So the question of how various nuclear factors move about and efficiently find their sites of action has long been a subject of interest and debate. This biological problem is complicated by the fact that most such factors function in large macro-molecular assemblies, with as many as 100 components that must interact at the right time and place. Relevant to this, many factors, including splicing factors, are both dispersed through the nucleoplasm and concentrated in certain nuclear compartments (Fig. 1). Two recent studies, one in The Journal of Cell Biology (Kruhlak et al. 2000) and the other in Nature (Phair and Misteli 2000...