Neuregulin 1

Neuregulin 1 (NRG-1, isoform HRG-beta2) belongs to the neuregulin/heregulin cytokine family consisting of variants of the four genes NRG1, NRG2, NRG3, and NRG4. More than 15 transmembrane and secreted protein isoforms exist for NRG-1, they are generated by alternative promoter usage and mRNA splicing. The different isoforms all contain immunoglobulin (Ig) and epidermal growth factor-like (EGF-like) domains. The EGF-like domain interacts with ErbB3 and ErbB4 tyrosine kinase receptors, resulting in tyrosine phosphorylation and NRG1 signaling. NRG proteins show distinct spatial and temporal expression patterns. These proteins are important for the development of the nervous system and the heart and in the regulation of neurotransmission.

Recombinant MESOkine® NRG-1 basic, bovine/porcine, is produced in the endosperm tissue of barley seed (Hordeum vulgare).

2xPBS, pH 7.4, sterile filtered through 0.2 μm filter

MESOkine® recombinant NRG-1 is purified from barley seeds resulting in an extract containing purified recombinant NRG-1 protein along with co-purified barley seed proteins. The amount of the recombinant NRG-1 protein is typically in the range of 20-30% of total purified protein content. The exact content of the growth factor is stated on the vials. The co-purified barley seed proteins may serve as stabilizing proteins that can prolong the lifetime of the recombinant protein during proper storage and may enhance the bioactivity of growth factors in standardized bioassays.

It is recommended to reconstitute the lyophilized protein in sterile buffered saline or a solution of your choice, preferably to a concentration of no more than 10-100 μg/ml. If needed the reconstituted material may be centrifuged at 3500G for 5 min or filtrated using a 0.45 micron filter. The lyophilized protein, though stable at room temperature for a few weeks, is best stored at -20°C. Reconstituted protein should be used immediately or stored in working aliquots at -20°C. Avoid repeated freeze-thaw cycles.

Each batch of MESOkine® growth factor is tested for bioactivity and verified to have comparable activity to a corresponding commercial source of highly purified (>95%) growth factor. The bioactivity of MESOkine® recombinant bovine/porcine NRG-1 was determined by its dose-dependent effect on the proliferation of MCF-7 cells. The ED50 for this effect using bovine/porcine NRG-1 is typically below 0.1 ng/ml corresponding to specific activity of > 10 x 10e6 U/mg. Optimal concentration should be determined for specific applications and cell lines.

MESOkine® NRG-1, bovine/porcine, recombinant, contains 65 amino acids and a 6 aa Histidine tag for a total length of 71 aa and has a predicted molecular mass of 8.3 kDa.