SDF-1 alpha (CXCL12)

Stromal cell-derived factor (SDF) -1 alpha and SDF-1 beta are the first cytokines initially identified using the signal sequence trap cloning strategy from a mouse bone-marrow stromal cell line. They are encoded by a single gene, PBSF, and arise by alternative splicing. The two proteins are identical except for the four amino acid residues that are present in the carboxy-terminus of SDF-1 beta and absent from SDF-1 alpha. SDF-1/PBSF is highly conserved between species. Human mature SDF-1 shares approximately 99% amino acid sequence identity with the mouse protein.