Noelin-1 (neuronal olfactomedin-related endoplasmic reticulum-localized-1), also known as olfactomedin-1 or pancortin, is a 75kD\ secreted extracellular matrix glycoprotein expressed in the brain.1-3 Alternate promoter usage and splicing creates four forms of Noelin (Noelin 1-4) that are combinations of a common central region with alternate N and C termini.3, 4 Noelin-1 is the longest of the four isoforms, encoding a 16 amino acid (aa) signal sequence and a 469 aa mature protein with a coiled coil region for multimerization and an olfactomedin-like domain. The shortest isoforms, Noelin-3 and -4, are truncated within the coiled-coil region and lack the olfactomedin-like domain.4 In the species tested, these isoforms appear to oppose actions of the longer isoforms.5 All isoforms are capable of forming homo- or heterodimers through cysteines in their common central region.2 The C-terminus of Noelin-1 (mouse aa 482-485) contains a putative endoplasmic reticulum retention sequence that has not been included in the protein.6 Mouse Noelin-1 (aa 17-481) shares > 99%, 99%, 97%, 96% and 93% aa identity with corresponding regions of rat, human, opossum, chicken and Xenopus Noelin-1, respectively. In vivo expression patterns differ somewhat between species.1 In chick early development, Noelin-1 shows highest concentration in areas that produce neural crest cells and is produced by migrating neural crest cells.7 Overproduction of Noelin-1 prolongs neural crest cell formation.7 Noelin-1 is also expressed in mouse neural crest, but not frog.1-3 All three species express Noelin-1 later in differentiating neural tissues in the spinal cord, brain and cranial ganglia.1-3 Recombinant protein corresponding to Ser2-Arg481 from mouse Noelin-1, fused with a 6X His-Tag at the C-terminus, expressed in a mouse myeloma cell line, NS0. Molecular Mass: Calculated molecular mass of ~55.7kD. As a result of glycosylation, the recombinant mouse Noelin-1 migrates as an ~80-90kD protein in SDS-PAGE under reducing conditions. Activity: Measured by its ability to induce epithelial to mesenchymal transformation of MDCKII cells. Treatment of MDCKII cells with 200ng/ml of recombinant mouse Noelin-1 for 3 days is sufficient to induce the transformation of MDCKII cells. Storage and Stability: Lyophilized and reconstituted products are stable for 6 months after receipt at -20C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20C. 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.
