Nuclear architecture: the cell biology of a laminopathy

Abstract

Lamin mutations cause muscular dystrophies, but the mechanism is unclear. A new study shows that lamin mutant worms display muscle-specific defects linked to altered subnuclear localization of heterochromatin, leading to altered gene expression.

Schematic representation of integrated plasmid arrays interacting with the nuclear lamina at the nuclear periphery. The lamina is a fibrous mesh under the nuclear envelope. Integrated arrays of plasmids in C. elegans localize at the nuclear periphery in wild type embryos (a), when they are not expressed (red array). After differentiation, a plasmid array having a muscle-specific promoter localizes to the nucleoplasm, where it is expressed (green array). In contrast, in embryos depleted of lamin (b), the plasmid arrays localize in the nucleoplasm and are frequently expressed, inappropriately. In worms expressing Y59C lamin (c), the arrays remain localized at the nuclear periphery after differentiation and are poorly expressed.