c/EBPβ Is a Major Regulatory Element Driving Transcriptional Activation of the CXCL12 Promoter

To elucidate the molecular mechanisms involved in the regulation of CXCL12 gene expression, we aim to define the molecular factors that operate at the transcriptional level. Basal, constitutive expression of CXCL12 was dependent on basic helix–loop–helix factors. Transcriptional up-regulation of the CXCL12 gene was induced by cellular confluence or inflammatory stimuli such as interleukin-1 and interleukin-6, in a CCAAT/enhancer binding protein β (c/EBPβ)-dependent manner. Chromatin immunoprecipitation assays confirmed c/EBPβ binding to a specific response element located at − 1171 of the promoter region of CXCL12. Our data show that c/EBPβ is a major regulatory element driving transcription of the CXCL12 gene in response to cytokines and cell confluence.