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The nuclear lamina is a highly organized scaffold beneath the nuclear envelope. It has a structural role and probably underpins interphase chromosome architecture by anchoring chromatin components. But what happens to the lamina when the envelope breaks down at mitosis, and how is order reestablished? Roland Foisner and co-workers have approached these questions by using live-cell imaging to track the behaviour of fluorescently tagged lamina components and chromatin at mitosis (see p. 6117). They find that a key lamina-associated protein, LAP-2α, specifically associates with telomeres during anaphase. As telophase progresses, it becomes clustered at so-called `core' structures in chromatin on either side of forming nuclei. The LAP-2α clusters bind to BAF - an essential DNA-binding protein - and also attract lamin A/C and another lamina component, emerin. Lamin B, the lamin B receptor and LAP-2β, by contrast, initially associate with more peripheral chromatin, before spreading to the core regions later on. The authors' findings are the first to implicate telomeres in assembly of the nuclear envelope/lamina. They also indicate that BAF-LAP-2α interactions might play an important part in the dynamic reorganization of chromatin after cell division.

© The Company of Biologists Limited
2004