title: Transcriptional regulation of the expression of macrophage colony stimulating factor.
abstract: The regulatory regions for transcriptional control of the MCSF gene are unknown. We examined regulatory control in a 774-bp murine MCSF promoter transfected into MC3T3-E1 osteoblast-like and COS-7 cells. Deletion of upstream sequence from -635 increased basal activity of the promoter by at least four-fold, an increase that was maintained when PU.1, NFkappaB and Egr1/Sp1 consensus sequences were subsequently removed. Mutagenesis identified a suppressor element between -635 and -642 from the transcriptional start site and an oligonucleotide representing this sequence was retarded by nuclear cell protein. TNFalpha (1 ng/ml), PTH (5x10(-8) M), and IL-1alpha (100 pg/ml), which increased MCSF protein secretion, failed to enhance the transcriptional rate of the full-length promoter. TNFalpha was able to stimulate transcription of a heterologous reporter transfected into COS-7 containing multiple copies of the murine MCSF NFkappaB site inserted before a minimal promoter. In contrast, deletion of the same NFkappaB response element increased basal activity in the native promoter. Thus, the NFkappaB sequence may act as a negative regulator in the context of the endogenous promoter. Our results indicate that constitutive transcriptional activity conferred by the MCSF promoter may be damped by a suppressor protein. Transcriptional regulation, however, does not appear to be a major stimulatory mechanism for MCSF secretion.
authors.affiliation: Department of Medicine, Veterans Affairs Medical Center and Emory University School of Medicine, VAMC-151, Dcatur, GA 30033, USA. jrubi02@emory.edu
authors.forename: J
authors.initials: J
authors.lastname: Rubin
authors.forename: D
authors.initials: D
authors.lastname: Fan
authors.forename: A
authors.initials: A
authors.lastname: Wade
authors.forename: T C
authors.initials: TC
authors.lastname: Murphy
authors.forename: H
authors.initials: H
authors.lastname: Gewant
authors.forename: M S
authors.initials: MS
authors.lastname: Nanes
authors.forename: X
authors.initials: X
authors.lastname: Fan
authors.forename: M
authors.initials: M
authors.lastname: Moerenhout
authors.forename: W
authors.initials: W
authors.lastname: Hofstetter
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D016723:Bone Remodeling / Q000187:drug effects / Q000235:genetics; D019556:COS Cells; D017931:DNA Primers / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D007375:Interleukin-1 / Q000494:pharmacology; D016173:Macrophage Colony-Stimulating Factor / Q000235:genetics*; D051379:Mice; D016296:Mutagenesis; D016328:NF-kappa B / Q000235:genetics; D010281:Parathyroid Hormone / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D017384:Sequence Deletion; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D017931:DNA Primers; D007375:Interleukin-1; D016328:NF-kappa B; D010281:Parathyroid Hormone; D014409:Tumor Necrosis Factor-alpha; D016173:Macrophage Colony-Stimulating Factor