GDF3 (previously called Vgr-2) is a TGF-beta superfamily member belonging to the growth/differentiation factor family. GDF3 is expressed in undifferentiated embryonic stem (ES) cells, adipose tissue and the brain. In ES cells, it maintains pluripotency and influences early cell fate decisions. For example, frog embryos injected with GDF3 develop a secondary dorsal axis and deletion of mouse GDF3 can produce defects in the anterior visceral endoderm of the pre-gastrulation embryo. In adipocytes, GDF3 is induced by a high fat diet and promotes adipogenesis. GDF3 has been reported to oppose BMPs functions and to have a nodal-like activity in the early development. The 366aa mouse GDF3 contains a 22aa signal sequence, a 230aa propeptide and a 114aa mature protein that contains one potential N-glycosylation site. Most of GDF3 is present as the prepro form, while mature GDF3 is presumably the secreted, active form. The mature protein contains the cysteine-knot structure that is conserved throughout family members. Since it lacks the fourth cysteine, which is responsible for the formation of inter-molecular disulfide bond, GDF3 may exist as a non-covalent homodimer. Mature mouse GDF3 shares 90%, 83% and 83% aa identity with rat, human and canine GDF3, respectively. Among family members, mature GDF3 is most similar to mouse BMP-6 (45% aa identity) and Xenopus VG-1 (52% aa identity). E. coli-derived, DNA sequence corresponding to Ala253-Gly366 from mouse GDF3 (Q07104). Molecular Mass: Based on N-terminal sequencing, the refolded mature mouse GDF-3 protein begins with Ala 253. The recombinant monomeric mouse GDF-3 has a calculated molecular mass of 13.1kD. Activity: Measured by its ability to bind with Activan RIB/ALK-4 Fc Chimera in the presence of recombinant mouse Cripto in functional ELISA. Immonilized recombinant mouse GDF3 at 1ug/ml (100ul/well) can bind recombinant human Activin RIB/Fc Chimera with an apparent KD <100nM. Storage and Stability: Lyophilized powder may be stored at -20C. Stable for 6 months after receipt at -20C. Reconstitute with sterile 4mM HCl. Aliquot to avoid repeated freezing and thawing. Store at -20C. Stable for 3 months after receipt. 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.
