title: Collaborative interaction of Oct-2 with Oct-1 in transactivation of lactogenic hormones-induced β-casein gene expression in mammary epithelial cells.
abstract: Octamer-binding transcription factor-1 (Oct-1) is found to mediate lactogenic hormones (prolactin and glucocorticoids, HP)-induced β-casein gene expression in mammary alveolar secretory epithelial cells (MECs). The mammary gland also expresses Oct-2 isoform. In this study, we show that Oct-2 is also involved in HP-induced β-casein expression. Oct-2 endogenously binds to the β-casein promoter in MECs, and HP induce Oct-2 binding activity via mechanisms other than increasing Oct-2 expression or inducing Oct-2 translocation to the nucleus. Oct-2 transactivates HP-induced β-casein gene expression and this function is exchangeable with Oct-1. In MECs, Oct-2 is found to physically interact with Oct-1 regardless of HP treatment. However, HP induce physical interactions of Oct-2 with both signal transducer and activator of transcription 5 (STAT5) and glucocorticoid receptor (GR). These results provided biochemical evidence that Oct-2 may form a heteromer with Oct-1 in induction of β-casein gene expression by HP in MECs.
authors.affiliation: Laboratory of Lactation and Metabolic Physiology, Department of Animal Science, University of Vermont, Burlington, VT 05405, USA.
authors.forename: Xi
authors.initials: X
authors.lastname: Qian
authors.affiliation: Laboratory of Lactation and Metabolic Physiology, Department of Animal Science, University of Vermont, Burlington, VT 05405, USA. Electronic address: fzhao@uvm.edu.
authors.forename: Feng-Qi
authors.initials: FQ
authors.lastname: Zhao
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002364:Caseins / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D024202:Electrophoretic Mobility Shift Assay; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation / Q000187:drug effects*; D005938:Glucocorticoids / Q000494:pharmacology*; D047468:Immunoprecipitation; D008321:Mammary Glands, Animal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D050811:Octamer Transcription Factor-1 / Q000235:genetics / Q000378:metabolism*; D027701:Organic Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D000075102:Organic Cation Transporter 2; D011388:Prolactin / Q000494:pharmacology*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D011965:Receptors, Glucocorticoid / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050799:STAT5 Transcription Factor / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects
chemical_list: D002364:Caseins; D005938:Glucocorticoids; D050811:Octamer Transcription Factor-1; D027701:Organic Cation Transport Proteins; D000075102:Organic Cation Transporter 2; C494166:Pou2f1 protein, mouse; D012333:RNA, Messenger; D011965:Receptors, Glucocorticoid; D050799:STAT5 Transcription Factor; C491012:Slc22a2 protein, mouse; D011388:Prolactin
keywords: Gene expression; Hormonal regulation; Milk protein; Octamer binding transcription factor; Transcriptional regulation