Transcriptome profiling of estrogen-regulated genes in human primary osteoblasts reveals an osteoblast-specific regulation of the insulin-like growth factor binding protein 4 gene.
Estradiol (E2) is believed to modulate physiological functions relevant to osteoblast biology through the actions of estrogen receptors (ERs) that in turn regulate the expression of target genes. The molecular effects of estrogen action in bone remain to be fully elucidated. This study reports a genome-wide molecular and computational analysis of the interaction between ER and regulatory elements on the DNA of target genes in human primary osteoblasts. Of approximately 54,000 gene probes surveyed in this study, a total of 375 genes were up-regulated and 418 genes were down-regulated on exposure to E2, with only 46 of these being direct target genes after 24 h, as determined by concomitant cycloheximide treatment. Computational analysis discovered several pathways where E2 co-regulates multiple functionally linked components. Examination of the genomic sequence of IGF binding protein 4 located ER response elements within the first intron. Using by chromatin immunoprecipitation, we show a site- and cell-specific recruitment of transcription factors to this newly identified regulatory region. Transient transfection studies revealed that this intronic region acts as a functional promoter in human osteoblasts. Taken together, this analysis provides a comprehensive gene transcription profile and identifies several genes of potential physiological importance in controlling estrogen-mediated signaling in primary osteoblasts.
Denger
Stefanie
S
European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany. denger@embl.de
Bähr-Ivacevic
Tomi
T
Brand
Heike
H
Reid
George
G
Blake
Jonathon
J
Seifert
Martin
M
Lin
Chin-Yo
CY
May
Klaus
K
Benes
Vladimir
V
Liu
Edison T
ET
Gannon
Frank
F
D001665:Binding Sites; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D003513:Cycloheximide / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D020869:Gene Expression Profiling / Q000379:methods*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000235:genetics* / Q000378:metabolism; D007438:Introns / Q000235:genetics; D008954:Models, Biological; D020411:Oligonucleotide Array Sequence Analysis; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection
D004967:Estrogens; D018974:Insulin-Like Growth Factor Binding Protein 4; D004958:Estradiol; D003513:Cycloheximide