Nuclear pores. can they expand and contract to regulate nucleocytoplasmic exchange?

Summary Recent evidence has revived the idea that translocation of macromolecules between nucleus and cytoplasm may be regulated via expansion and contraction of the entire diameter of the nuclear pore complex. The present investigation does not support this hypothesis.Acknowledgments. We are indebted to Dr J.H.M. Willison for discussion of his and Dr Rajaraman's results before their publication. We also wish to thank Dr C. Thurston, Dr D.H. Williamson and Dr K. Lambert for providing some of the specimens used in this investigation. N.J. Severs acknowledges the support of the Science Research Council and the Cancer Research Campaign.