SFRP3, Recombinant, Mouse (Secreted Frizzled Related Protein 3, FRZB, Fritz, Frzb1)

Secreted Frizzled Related Protein 3 (sFRP-3) was originally identified in bovine cartilage for its chondrogenic ability. Human, mouse, chick and Xenopus clones have also been isolated. sFRP-3 is often referred to as FRZB, other names also include Fritz, Frzb1, and FRP-3. At the amino acid sequence level, sFRP-3 is highly conserved. The mouse protein shares 76% identity with Xenopus, and 92% with human proteins. The gene for mouse sFRP-3 has been localized to the central region of chromosome 2. Murine sFRP-3 is expressed in the primitive streak during gastrulation, as well as in the retina, foregut diverticulum, nervous system, and posterior mesoderm during development. In adult tissues, sFRP-3 expression, as determined by Northern blot, is detected in the heart, brain, spleen, skeletal muscle, kidney and testis. The N-terminal portion of sFRP-3 protein shows 50% amino acid identity to the corresponding region of the Drosophila frizzled gene product, a receptor for Wg/Wnt signals. The similarity of sFRP-3 with frizzled proteins is restricted to the N-terminal cysteine-rich domain (CRD) that contains at least ten cysteine residues with highly conserved spacing between them. sFRP-3 was subsequently shown to be a soluble antagonist of Wnt signals. It lacks all transmembrane domains of frizzled proteins but retains the ability to bind Wnts. Ectopic expression of sFRP-3 mRNA has been shown to interfere with the induction of secondary axes in Xenopus embryos injected with Xwnt-8 mRNA (Hoang et al., 1996, J. Biol. Chem. 271:26131, Leyns et al., 1997, Cell 88:747,, Wang et al., 1997, Cell 88:757, Mayr et al., 1997, Mech. Dev. 63:109, Rattner et al., 1997, PNAS 94:2859). A DNA sequence encoding the mature mouse sFRP-3 protein sequence Ala33-Ser323 was fused to a 6X histidine tag at the carboxy-terminus. The fusion protein was expressed in a mouse myeloma cell line, NS0. Swiss/UniProt Accession: P97401 , Molecular Mass: , Based on N-terminal sequencing, the mature mouse sFRP-3 protein starts at Ala33 and has a, calculated molecular mass of 34kD. As a result of glycosylation, the recombinant protein migrates as an ~37kD protein in SDS-PAGE under reducing conditions. Activity: Measured by its ability to inhibit proliferation in MC3T3-E1 mouse preosteoblast cells. ED50 1.5-6.0ug/ml. Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 6 months after receipt at -20°C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -70°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.