Peter Askjaer heads the Nuclear Dynamics in Cell and Developmental Biology at the Centro Andaluz de Biología del Desarrollo in Seville. Development of an organism requires precise orchestrating of numerous biological processes. Control of gene expression and accurate cell division are of paramount importance to all forms of life and involve extensive interactions between proteins and chromatin. In eukaryotic cells, access to the genome is controlled by the nuclear envelope (NE), which serves as a selective permeability barrier and chromatin organizer. Through a systematic depletion approach, his team has identified several nucleoporins that are essential for the correct segregation of chromosomes and for reforming the NE after mitosis. To further analyse NE proteins, they combine advanced light microscopy, genome-wide RNAi and biochemical approaches.