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Analysis of human breast cancer nuclear proteins binding to the promoter elements of the c‐ myc gene
Author(s) -
Miller Teresa L.,
Jin Yan,
Sun JianMin,
Coutts Amanda S.,
Murphy Leigh C.,
Davie James R.
Publication year - 1996
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(19960315)60:4<560::aid-jcb12>3.0.co;2-l
Subject(s) - promoter , chromatin , gene , microbiology and biotechnology , biology , dna , cancer cell , hormone response element , nuclear protein , estrogen receptor , nuclear receptor , binding site , gene expression , transcription factor , cancer research , breast cancer , cancer , genetics
The expression of the c‐ myc gene is essential for the proliferation of both hormone‐dependent and ‐independent human breast cancer cells. The regulation of c‐ myc gene expression in MCF‐7 (hormone‐dependent, estrogen‐receptor (ER)‐positive) and MDA MB 231 (hormone‐independent, ER‐negative) human breast cancer cells differs, with the c‐ myc gene of MCF‐7 but not MDA MB 231 cells being regulated at the transcriptional level by estrogen. We have shown previously that the DNAase I hypersensitive (DH) sites in the c‐ myc chromatin of hormone‐dependent and ‐independent human breast cancer cells were similar, with the exception of DH site II 2 , DH site II 2 , which maps near the P0 promoter, was less sensitive in hormone‐dependent than in hormone‐independent cells. As DH sites generally indicate the presence of sequence‐specific DNA‐binding proteins, we undertook a study to identify the nuclear proteins isolated from MCF‐7 and MDA MB 231 cells that bound to the P0 and P2 promoter regions of the c‐ myc gene in vitro. The studies presented here provide evidence that Sp1 and/or Sp1‐like proteins bind to the P0 and P2 promoter regions of the c‐ myc gene of MCF‐7 and MDA MB 231 cells. Furthermore, evidence is presented for the presence of several previously unidentified sequence‐specific DNA‐binding proteins binding to these promoters. The DNA‐binding activities of these latter proteins differed in the nuclear extracts of the MCF‐7 and MDA MB 231 human breast cancer cells. © 1996 Wiley‐Liss, Inc.