DNER, Recombinant, Human, Fc Chimera (Delta and Notch-like Epidermal Growth Factor-related Receptor,

DNER (Delta/Notch-like EGF-related receptor), also known as BET (brain-specific EGF-like transmembrane protein), is a type I transmembrane glycoprotein of the Notch/Delta family (1, 2). In the mouse, DNER has been detected as 90, 120 and 150kD forms which are probably variably glycosylated (1, 2). DNER is specifically expressed on nonaxonal areas of post-mitotic neurons, especially Purkinje cells, but also cortical and hippocampal pyramidal neurons and immature cerebellar granule cells (1-5). After expression on the cell surface, DNER is removed from axonal membranes, but remains on somatodendritic membranes (1, 3, 6). A portion of DNER is found within endosomes (1, 3, 6). Human DNER cDNA encodes 737aa that include a 25 aa signal sequence, a 615 aa extracellular domain (ECD) containing ten distinct Delta/Notch-like EGF-like repeats, a 21 aa transmembrane sequence, and a 76 aa cytoplasmic domain. The human DNER ECD shares 89%, 89% and 88% aa sequence identity with mouse, rat and bovine DNER, respectively. DNER is a Notch ligand, but is considered a non-classical ligand because it lacks the usual DSL Notch binding motif (5, 7). Instead, Notch interacts with the two EGF-like repeats closest to the N-terminus of DNER (5). Mice lacking DNER show impaired cerebellar functions and delayed Purkinje cell-mediated maturation of Notch- expressing Bergmann glia during cerebellar development (4, 5). DNER associates with protein tyrosine phosphatase z (PTPz), which is the receptor of pleiotrophin (PTN). PTPz-PTN-DNER signaling has been implicated in the regulation of neuritogenesis (3). Expression of DNER in glioblastoma stem-like cells inhibits formation of neurospheres in vitro, while in vivo it induces differentiation and inhibits growth of xenografts, thus acting as a tumor suppressor (7). Expression of DNER in adipose-derived human mesenchymal stem cells and mouse auditory hair cells have also been shown (8, 9). Source: Recombinant corresponding to aa29-637 of human DNER at N-terminal and aa100-330 human IgG1, expressed in mouse myeloma cell line, NS0. Molecular Weight: ~90.9kD, Endotoxin Level: <1EU/1ug (LAL), Biological Activity: Measured by its ability to inhibit Pleiotrophin-induced neurite outgrowth of E16-E18 rat embryonic cortical neurons. When 4x10e4 neurons/well are added to 96-well plate containing serial dilutions of recombinant human DNER Fc chimera and immobilized recombinant human Pleiotrophin (1ug/ml), neurite outgrowth is significantly inhibited in a dose dependent manner. The ED50 for this effect is typically 0.4-1.6ug/ml. Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 6 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.