The lamin are type V intermediate filaments which provides structure and mechanical support to the cell nucleus. Besides, they play important roles in nuclear stability, reassembly of the nuclear envelope during mitosis, chromatin structure, anchoring of nuclear pore complexes and gene expression. Lamin B1 (LMNB1) is essential for proper chromosome condensation in interphase nuclei. It also participates in the distribution of heterochromatin and modulation of gene expression and splicing. It plays a key role in DNA replication, cellular aging and stress responses. Innoprot fluorescent LMNB1 Cell Line allows to assay compounds for their ability to induce apoptosis analyzing their nuclear stability.

To validate the fluorescent LMNB1 Cell Line as apoptosis model, we incubate the cells with staurosporine. In non-apoptotic cells TagRFP appears localized in nuclear envelope but after treatment, activated caspase family proteases cleave lamin, resulting in the loss of its structure and detachment from chromatine. Tagged lamin appears disassembled and forms round aggregates. The assay was developed and optimized using the BD Pathway HCS Reader and Attovision Compartimentalization Software. The parameters analyzed in order to check the apoptosis degree are eccentricity and perimeter of the nucleus.