title: Regulation of insulin-like growth factor binding protein-1 promoter activity by FKHR and HOXA10 in primate endometrial cells.
abstract: Insulin-like growth factor binding protein-1 (IGFBP-1) is abundantly expressed in the liver and decidualized endometrium. FKHR, a FOXO forkhead transcription factor, stimulates IGFBP-1 promoter activity in liver cells through the insulin response sequences (IRSs). HOXA10, a homeobox transcription factor, is important in the decidualization process. Here we show that FKHR and HOXA10 are expressed in baboon endometrium during the menstrual cycle and pregnancy. Levels are lowest during the follicular phase and highest in pregnancy. Reporter gene studies reveal that FKHR stimulates both baboon and human IGFBP-1 promoter activity, whereas HOXA10 alone has a relatively weak effect. When FKHR and HOXA10 are expressed together, promoter activity is markedly up-regulated, which is indicative of cooperativity. A DNA binding-deficient FKHR mutant fails to stimulate promoter activity, even in the presence of HOXA10, and deletion or mutation of IRSs also disrupts the effect of FKHR and cooperativity with HOXA10. Conversely, the IRS region placed upstream of the 31 base pair IGFBP-1 minimal promoter is sufficient to mediate effects of FKHR and cooperativity with HOXA10. Pull-down studies reveal physical association between GST-FKHR and (35)S-HOXA10. These studies show that FKHR and HOXA10 interact directly and can function cooperatively to stimulate IGFBP-1 promoter activity in endometrial cells and perhaps in other settings.
authors.affiliation: Department of Obstetrics and Gynecology, University of Illinois at Chicago College of Medicine and VA Chicago Healthcare System (West Side), Chicago, Illinois 60612, USA.
authors.forename: J Julie
authors.initials: JJ
authors.lastname: Kim
authors.forename: Hugh S
authors.initials: HS
authors.lastname: Taylor
authors.forename: G Eda
authors.initials: GE
authors.lastname: Akbas
authors.forename: Isabelle
authors.initials: I
authors.lastname: Foucher
authors.forename: Alain
authors.initials: A
authors.lastname: Trembleau
authors.forename: Randal C
authors.initials: RC
authors.lastname: Jaffe
authors.forename: Asgerally T
authors.initials: AT
authors.lastname: Fazleabas
authors.forename: Terry G
authors.initials: TG
authors.lastname: Unterman
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004717:Endometrium / Q000378:metabolism*; D005260:Female; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; D005786:Gene Expression Regulation; D000080905:Homeobox A10 Proteins; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D010215:Papio; D011247:Pregnancy; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; C085126:FOXO1 protein, human; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; D000080905:Homeobox A10 Proteins; D018398:Homeodomain Proteins; D018970:Insulin-Like Growth Factor Binding Protein 1; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C092119:Hoxa10 protein, mouse; D004247:DNA