The molecular basis of lamin-specific chromatin interactions.

In the cell nucleus, chromatin is anchored to the nuclear lamina, a network of lamin filaments and binding proteins that underly the inner nuclear membrane. The nuclear lamina is involved in chromatin organization through the interaction of lamina-associated domains within the densely packed heterochromatin regions. Using cryo-focused ion beam milling in conjunction with cryo-electron tomography, we analyzed the distribution of nucleosomes at the lamin-chromatin interface at the nanometer scale.

Biochemical properties of chromatin domains define genome compartmentalization.

Chromatin three-dimensional (3D) organization inside the cell nucleus determines the separation of euchromatin and heterochromatin domains. Their segregation results in the definition of active and inactive chromatin compartments, whereby the local concentration of associated proteins, RNA and DNA results in the formation of distinct subnuclear structures. Thus, chromatin domains spatially confined in a specific 3D nuclear compartment are expected to share similar epigenetic features and biochemical properties, in terms of accessibility and solubility.