Frizzled 8, Fc Chimera, Recombinant, Mouse (FZD8)

Members of the Frizzled family of proteins serve as receptors for the Wnt signaling pathway. The founding member of this family was identified in Drosophilia based on its role in tissue polarity in the adult cuticle and named for the disorganized appearance of bristle hairs on the mutant. Mouse Frizzled-8 (mFrz-8) was originally cloned in a PCR screen to identify additional Frizzled family members in vertebrates. There are nine murine Frizzled genes and 10 human Frizzled genes identified to date. The predicted structure of Frizzled proteins is similar among all family members, containing a divergent N-terminal signal peptide, a highly conserved extracellular cysteine-rich domain, a seven-pass transmembrane region, and a variable-length C-terminal tail. The most conserved regions of the Frizzled proteins are the extracellular cysteine-rich domain (CRD) which spans approximately 120aa residues and contains 10 invariant cysteines, and the seven transmembrane domains. Mouse Frizzled-8 is 685 aa residues long and shows 95% and 82% amino acid identity to human and Xenopus Frizzled-8, respectively. Like other family members, Frizzled-8 has a complex expression pattern in the mouse embryo. It is expressed in the neural tube, brain, eye, somites, gut and bronchial arches. One of the best-characterized Wnt signal transduction pathways is the canonical Wnt/b-catenin pathway. It is involved in diverse biological mechanisms such as dorsal/ventral development in Xenopus embryos and mammalian tumor formation, acting via stabilization of b-catenin. Frizzled-8 is implicated in this pathway based on its ability to bind Wnt ligands that stimulate b-catenin stabilization and to influence the formation of secondary axes in Xenopus embryos. The mFrz-8 CRD has been demonstrated to bind cell surface Xenopus Wnt-8 (Xwnt-8) protein, indicating that this region is sufficient for binding ligand. Source: N- Frizzled-8 (Met -Pro173)- IEGRMD- IgG1 (Pro100-Lys330)- C, A DNA sequence encoding amino acid residues 1-173 of the extracellular Cysteine-Rich Domain (CRD) domain of Frizzled-8 (Wang, Y. et al., 1996, J. Biol. Chem. 271: 4468-4476) was fused to the Fc region of human IgG1 via a peptide linker. The chimeric protein was expressed in a mouse myeloma cell line, NS0. Molecular Mass: The recombinant mature mouse Frizzled-8/Fc chimera, generated by proteolytic removal of the signal peptide region, is a disulfide-linked homodimeric protein. Based on N-terminal sequencing, two structural forms of the recombinant mature Frizzled-8/Fc chimera subunits with Ala25 and Ala28 at the amino terminus are present. Each monomer of rmFrizzled-8/Fc has a calculated molecular mass of ~43kD. As a result of glycosylation, the recombinant protein migrates as a 55-60kD protein in SDS-PAGE under reducing conditions. Activity: Measured by its ability to interfere with the axis-inducing activity of Xwnt-8 mRNA in early Xenopus embryos. In a population of embryos, addition of 1ng of mouse Frizzled-8/Fc protein per embryo resulted in 50-100% reduction in the number of secondary axes produced by 10-20pg of Xwnt-8 mRNA. Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterile 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.,