Cell type-specific bidirectional regulation of the glucocorticoid-induced leucine zipper (GILZ) gene by estrogen.
Estrogen has numerous beneficial physiological actions; however, by acting as a mitogen, it plays a significant role in the induction and maintenance of breast cancer. Although the positive effects of estrogen on gene expression are well described, negative gene regulation is not. Using microarray analysis, we identified 27 genes that were up-regulated and 20 that were down-regulated by estrogen in MCF-7 human breast cancer cells. One gene encoding GILZ (glucocorticoid-induced leucine zipper protein), a putative apoptosis-regulating transcription factor, is rapidly down-regulated by estrogen in these cells. Estrogen antagonists block the down-regulation. The region of the GILZ promoter between nucleotides -104 and -69 mediates both basal activity and estrogen-dependent down-regulation in MCF-7 cells. This region contains a functional Oct-1 binding site and a cyclic AMP response element binding protein (CREB) binding site. The same DNA region mediates up-regulation by estrogen in HeLa and HEK293 cells, indicating that cell-specific factors are involved in estrogen regulation of this gene. The estrogen receptor (ER) is present in GILZ promoter protein complexes, but it does not bind directly to the promoter itself, as the DNA-binding domain of the estrogen receptor is not required for down-regulation. Elimination of the CREB binding site blocks both basal activity and estrogen regulation. Our results suggest that ER action at the CRE may mediate estrogen-dependent, cell-specific regulation of this gene.
Tynan
Sharon H
SH
Reproductive Therapeutics, Johnson and Johnson Pharmaceutical Research and Development, L.L.C., 1000 Route 202 South, Room B-115, P.O. Box 300, Raritan, NJ 08869, USA.
Lundeen
Scott G
SG
Allan
George F
GF
D001483:Base Sequence; D001665:Binding Sites; D001943:Breast Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D004965:Estrogen Antagonists / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects*; D006367:HeLa Cells; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D016350:Leucine Zippers / Q000235:genetics; D008156:Luciferases / Q000378:metabolism; D008969:Molecular Sequence Data; D050811:Octamer Transcription Factor-1; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014407:Tumor Cells, Cultured
D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D004965:Estrogen Antagonists; D004967:Estrogens; D050811:Octamer Transcription Factor-1; C494165:POU2F1 protein, human; C404226:TSC22D3 protein, human; D014157:Transcription Factors; D008156:Luciferases