title: Involvement of 5'-flanking kappaB-like sites within bcl-x gene in silica-induced Bcl-x expression.
abstract: The present study investigated the involvement of the transcription factor NF-kappaB in the expression of an anti-apoptotic gene, bcl-x, using a murine macrophage cell line and peritoneal macrophages from both wild type (p50(+/+)) and NF-kappaB p50 gene knockout (p50(-/-)) mice. Increased expression of Bcl-x protein was observed in native and silica-exposed p50(-/-) macrophages in which the NF-kappaB p65-containing complex was predominantly induced. Co-transfection experiment using a bcl-x promoter reporter construct and an expression vector for NF-kappaB p50 or p65 indicates that p65, but not p50, up-regulates the promoter activity of the bcl-x gene. DNA sequence analysis revealed that there are several kappaB-like sites within the 5'-flanking region of the bcl-x gene. Electrophoretic mobility shift assay suggested differences in binding of the NF-kappaB complexes to these putative NF-kappaB binding sites of the bcl-x gene.
authors.affiliation: The Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505, USA.
authors.forename: F
authors.initials: F
authors.lastname: Chen
authors.forename: L M
authors.initials: LM
authors.lastname: Demers
authors.forename: V
authors.initials: V
authors.lastname: Vallyathan
authors.forename: Y
authors.initials: Y
authors.lastname: Lu
authors.forename: V
authors.initials: V
authors.lastname: Castranova
authors.forename: X
authors.initials: X
authors.lastname: Shi
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D005786:Gene Expression Regulation / Q000187:drug effects*; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*; D011994:Recombinant Proteins / Q000096:biosynthesis; D012822:Silicon Dioxide / Q000494:pharmacology*; D014162:Transfection; D051020:bcl-X Protein
chemical_list: C494812:Bcl2l1 protein, mouse; D016328:NF-kappa B; D019253:Proto-Oncogene Proteins c-bcl-2; D011994:Recombinant Proteins; D051020:bcl-X Protein; D012822:Silicon Dioxide