A journey into the nucleus

Abstract

The EMBO Conference on Nuclear Structure and Dynamics took place between 1 and 5 September 2007, in Montpellier, France, and was organized by G. Cavalli, C. Cremer, S. Gasser, T. Pederson, F. Uhlmann and R. van Driel. ![][1] The basic processes that are responsible for the maintenance and expression of the genome are relatively well understood at the biochemical level, but we still have much to learn about how these processes occur in their physiological context—the cell nucleus—and how they are regulated and coordinated. The second EMBO Conference on Nuclear Structure and Dynamics brought together 240 scientists to discuss the interplay between nuclear structure and genome function. The scope of the meeting was broad, and the speakers covered various topics and experimental approaches. Here, we highlight some of the main issues that were discussed at the conference. Various types of chromatin are segregated in the nucleus. Heterochromatin—which is gene‐poor, rich in proteins that promote gene silencing and characterized by low levels of transcriptional activity—is typically located near the nuclear envelope and around the nucleolus. For this reason, the nuclear periphery has been traditionally regarded as a repressive compartment for gene expression. However, recent studies have shown that the association of actively transcribed genes with nuclear pores gives rise to high levels of expression (for example, Taddei et al , 2006). By using the DNA adenine methyltransferase identification (DamID) technique, B. Van Steensel (Amsterdam, The Netherlands) identified approximately 1,300 lamin‐associated domains (LADs) in human cells and showed that such chromatin regions are characterized by low gene density. LAD borders are flanked by promoters or by CCCTC‐binding factor (CTCF)‐binding sites that potentially act as insulators. B. Kalverda (Amsterdam, The Netherlands) analysed sequences associated with nuclear‐pore proteins in Drosophila cells. In contrast to the lamin‐interacting DNA, the nucleoporin‐interacting sequences contain highly expressed genes, and are … [1]: /embed/graphic-1.gif