U2OS-CRISPR-TPR-SNAP Cells

U2OS-CRISPR-TPR-SNAP is a genome-edited human osteosarcoma cell line derived from U2OS cells in which the endogenous TPR (Translocated Promoter Region) gene has been modified using CRISPR/Cas9 technology to encode an in-frame SNAP tag. TPR is a large coiled-coil nucleoporin that localizes to the nuclear basket on the nucleoplasmic side of the nuclear pore complex (NPC). By tagging TPR at its endogenous locus, the fusion protein is expressed under native regulatory control, preserving physiological expression levels and maintaining proper incorporation into the nuclear basket structure.

The SNAP tag enables covalent labeling of TPR with benzylguanine-conjugated fluorescent substrates in live or fixed cells, allowing highly specific and stable visualization. In U2OS-CRISPR-TPR-SNAP cells, labeled TPR displays a characteristic punctate ring-like distribution at the nuclear envelope, corresponding to NPC-associated nuclear basket structures. This system is well suited for quantitative fluorescence microscopy, super-resolution imaging, pulse-chase labeling, and dynamic studies of nuclear basket assembly and turnover. The flat morphology and large nuclei of U2OS cells facilitate high-resolution imaging of nuclear envelope-associated structures.

TPR plays critical roles in mRNA export, nuclear transport regulation, chromatin organization at the nuclear periphery, and spatial genome organization. TPR is also implicated in the formation of nuclear transport-related subcompartments and in the exclusion of heterochromatin from nuclear pore-associated regions. U2OS-CRISPR-TPR-SNAP provides a physiologically relevant model for dissecting the architecture and dynamics of the nuclear basket, investigating nucleocytoplasmic trafficking mechanisms, and studying nuclear envelope-associated chromatin interactions under endogenous expression conditions.