Abstract
The nucleus in eukaryotic cells is an important organelle to maintain, replicate and express genetic information on DNA. While little is known about the basis underlying the relationship between the structure and function in nuclei, recent studies on molecular kinetics in living cells have shown that most macromolecules, like proteins and RNAs, diffuse freely in the crowded soup, suggesting that the recruitment of transcription/repair factors is stochastic by random collision of diffusible molecules to relatively static chromatin. Nuclear substructures like nuclear 'speckle's are also built as steady-state structures by rapid association and dissociation of their components.
