Analysis of the activity of nuclear export signals using fluorescent BSA conjugates.

Here we demonstrate that fluorescein-labeled BSA conjugated with a mixture of nuclear import and export signals can be used to evaluate export activity. The method is based on the assumption that the intracellular distribution of the labeled conjugate [nuclear/cytoplasmic (N/C) fluorescent ratio] is dependent on the relative activity of the import versus the export signals. Using BALB/c cells as a model system, it was shown that this assumption is correct.

Macromolecular exchanges between the nucleus and cytoplasm.

The control of transcription and translation is of fundamental importance in cell biology. In this regard, the nuclear envelope is in a unique position to contribute to the regulation of these events, by directing macromolecular exchanges between the nucleus and cytoplasm. Such exchanges occur through the nuclear pore complexes, mainly by signal-mediated processes.