Minimal promoter components of the human growth/differentiation factor-5 gene

Growth/differentiation factor-5 (GDF-5) is a new member of the BMP family s upposed to be involved in chondrogenesis. We cloned the human GDF-5 gene fr om lambda phage library and sequenced its 3.5-kb 5'-flanking region. The tr anscription start site was mapped by 5'-RACE to the sequence that coincides with the initiator element. Electrophoresis mobility shift assays (EMSA) d emonstrated a zinc finger transcription factor, YY1, to bind to the sequenc e surrounding the transcription start site. To localize positive and negati ve regulatory elements in the GDF-5 5'-upstream region, we constructed a se ries of progressively deleted promoter-reporter plasmids. The transient tra nsfection assay with human osteoblastic Hos cells indicated that a minimal enhancer element resides within -117 to -27 relative to the transcription i nitiation site. Since the GDF-5 promoter was active even in fibroblastic L cells, a mechanism governing its chondrocyte-restrictive expression needs t o be explored. (C) 1999 Academic Press.