This three-year award will support U.S.-France cooperative research in cell biology between Howard J. Worman of Columbia University and Jean-Claude Courvalin of the Institut Jacques Monod, University of Paris VI. The objective of their research is to study the mechanism of nuclear envelope or membrane reassembly that takes place at the end of cell division. They will focus on two nuclear- specific membrane proteins that have been identified in nuclear envelope reassembly. The U.S. investigator brings to this collaboration expertise in molecular biology. The engineering of the cDNA clones for the expression of the protein will be performed in his laboratory. This is complemented by the French investigator's expertise in cell biology. Most of the biochemical and morphological experiments on the nuclear envelope reassembly will be carried out in his laboratory. This joint effort will advance fundamental understanding of the cell nucleus and the role of these proteins in nuclear envelope reassembly.