ABSTRACT
AIM: To determine whether the high mobility group protein I (HMGI) is able to bind to the upstream sequence of platelet-derived growth factor B-chain gene and to characterize the HMGI-binding AT-rich regions. METHODS: Recombinant human HMGI (rhHMGI) protein was prepared and electrophoresis mobility shift assay (EMSA) was used. RESULTS: The binding of rhHMGI to PDGF-B (-1 758 / +43 bp) was observed in vitro. Two major HMGI-binding fragments -1 392 / -1 180 bp and -188 / +43 bp were identified, which contained the same AT-rich sequence TTTATAAA (-1 333 / -1 326 bp, -1 314 / -1 307 bp and -30 / -23 bp). An oligonucleotide bound to the TTTATAAA and the GAGACC, the core sequence of the shear stress response element of the PDGF-B, could also bind to the HMGI. Furthermore, HMGI facilitated the binding of NF-?B to the GAGACC in the oligonucleotide. CONCLUSION: The HMGI could bind to the upstream sequence of the PDGF-B gene via the AT-rich sequence TTTATAAA, which may play a role in the transcriptional regulation of the PDGF-B gene.