The HMG-I/Y proteins bind chromatin and regulate gene expression by relieving histone-mediated repression of transcription. Their elevated expression has been correlated to neoplastic transformation, although the mechanism by which this occurs has not been clear. Wood et al. now report that the transcription factor c-Myc, also implicated in cell growth and transformation, regulates HMG-I/Y expression. The authors demonstrate that binding of c-Myc, and its protein partner Max, to a consensus DNA binding site in the promoter region of HMG-I/Y, regulates transcription and HMG-I/Y expression. Induction of HMG-I/Y expression by serum was reduced in Myc-deficient fibroblasts. Mutation of the c-Myc binding site reduced HMG-I/Y expression in cells by 60%, suggesting that other proteins also contribute to HMG-I/Y regulation.
Wood, L.J., Mukherjee, M., Dolde, C.E., Xu, Y., Maher, J.F., Bunton, T.E., Williams, J.B., and Resar, L.M.S. (2000) HMG-I/Y, a new c-Myc target gene and potential oncogene. Mol. Cell. Biol. 20: 5490-5502. [Abstract] [Full Text]