• Purity

  >95%, by SDS-PAGE with silver staining

• Endotoxin Level

  <0.10 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its ability to inhibit adipocyte differentiation of mouse 3T3‑L1 mouse embryonic fibroblast adipose-like cells. Smas, C.M.     et al. (1993) Cell     73:725. Recombinant Mouse Pref‑1/DLK1/FA1 at 2.5 μg/mL will inhibit adipocyte differentiation by more than 50%.

• Source

  Mouse myeloma cell line, NS0-derived Ala24-Gln305, with a C-terminal 6-His tag

• Accession #

• N-terminal Sequence    
  Analysis

  Ala24

• Predicted Molecular Mass

  31 kDa

• SDS-PAGE

  49-66 kDa, reducing conditions

Background: Pref-1/DLK1/FA1

Mouse Pref-1 (preadipocyte factor 1), also known as Dlk-1 or FA1, belongs to the Notch/Delta/Serrate family of EGF-like repeat-containing proteins that act as ligands in the Notch signaling pathway (1-3). Mouse Pref-1 is synthesized as a 385 amino acid (aa) precursor consisting of a 23 aa signal sequence, a 282 aa extracellular region, a 24 aa transmembrane segment, and a 56 aa cytoplasmic tail. The extracellular region contains six tandem EGF-like repeats, a juxtamembrane region, and multiple sites for O- and N-glycosylation. Heterogeneous transmembrane forms of Pref-1, ranging from 50 to 60 kDa, can be attributed to variability in glycosylation (2-4). In addition to full-length Pref-1A, alternative splicing of the juxtamembrane and EGF-like repeat regions generates three major short forms, Pref-1B, -1C, and
-1D (5). Proteolytic cleavage at one of two extracellular sites in Pref-1A and 1B can produce two soluble forms: a 50 kDa large form and a 24-25 kDa small form (2, 5, 6). Processing of Pref-1C and Pref-1D, by contrast, can produce only small soluble forms. Only the large soluble form demonstrates biological activity (5). The ECD of mature mouse Pref-1 shares 94% and 83% aa sequence identity with the ECD of human and rat Pref-1, respectively. Pref-1 is widely expressed during embryogenesis (2). In adults, Pref-1 expression is restricted to preadipocytes, pancreatic beta  cells, thymic stromal cells, and cells of the adrenal and pituitary glands
(1, 7-9). Tumors of neuroendocrine origin have been found to express Pref-1 (10). Down-regulation of Pref-1 in preadipocytes is associated with differentiation into mature adipocytes (1-7). Pref-1 also regulates the differentiation of skeletal stem cells, thymocytes, and adrenal gland cells and inhibits hormone secretion in pituitary cells (1). Pref-1 has also been shown to inhibit preadipocyte proliferation (11, 12).

• References:

1. Ansell, P.J. et al. (2007) Mol. Cell. Endocrinol. 271:55.

2. Smas, C.M. and H.S. Sul (1993) Cell 73:725.

3. Sul, H.S. (2009) Mol. Endocrinol. 23:1717.

4. Smas, C.M. et al. (1994) Biochemistry 33:9257.

5. Mei, B. et al. (2002) Biochem. J. 364:137.

6. Wang, Y. and H.S. Sul (2006) Mol. Cell. Biol. 26:5421.

7. Wang, Y. et al. (2010) Mol. Cell. Biol. 30:3480.

8. Friedrichsen, B.N. et al. (2003) J. Endocrinol. 176:257.

9. Hedlund, G.P. et al. (2003) In Vivo 17:1.

10. Yin, D. et al. (2006) Oncogene 25:1852.

11. Traustadottir, G.A. et al. (2013) Adipocyte 2:272.

12. Mortensen, S.B. et al. (2012) Diabetes 61:2814.

• Long Name:

  Preadipocyte Factor-1/Protein delta Homolog 1/Fetal Antigen 1

• Entrez Gene IDs:

  8788 (Human); 13386 (Mouse)

• Alternate Names:

  delta-like 1 homolog (Drosophila); DLK; DLK1; DLK-1; FA1; FA1fetal antigen 1; pG2; pG2delta-like homolog (Drosophila); preadipocyte factor 1; Pref1; Pref-1; protein delta homolog 1; secredeltin; ZOG