title: Differentiation status of cultured murine keratinocytes modulates induction of genes responsive to 2,3,7,8-tetrachlorodibenzo-p-dioxin.
abstract: Primary murine keratinocytes were cultured in a chemically defined, serum-free medium which facilitated manipulation of their differentiation status. Exposure of basal cell and differentiating cultures to >/= 0.1 nM 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) preferentially elevated 7-ethoxyresorufin O-deethylase specific activities in differentiating cultures (28-fold versus 4-fold increases after 36 h of exposure). Semiquantitative reverse-transcription polymerase chain reaction (RT-PCR) analyses demonstrated the presence of constitutive mRNA transcripts corresponding to four known TCDD-inducible genes (e.g., Cyp1a1, Cyp1b1, Ahd4, and Nmo1) in both differentiating and proliferating cultures of murine keratinocytes. All four genes were induced in differentiating cultures following exposure to TCDD. No induction occurred in comparably treated basal cell cultures. Indirect immunofluorescence analyses demonstrated the presence of aryl hydrocarbon receptor (AHR) and aryl hydrocarbon receptor nuclear translocator (ARNT) proteins in both basal and differentiating keratinocytes. Both proteins appeared to be associated with the nucleus and their nuclear association was independent of prior exposure to TCDD. These studies suggest that AHR activation in murine skin is regulated as a function of the keratinocyte differentiation program.
authors.affiliation: Institute of Chemical Toxicology, Wayne State University, Detroit, Michigan 48201, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Jones
authors.forename: J J
authors.initials: JJ
authors.lastname: Reiners
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000096:biosynthesis; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D002451:Cell Compartmentation; D002454:Cell Differentiation; D002467:Cell Nucleus; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D019363:Cytochrome P-450 CYP1A1 / Q000096:biosynthesis; D065633:Cytochrome P-450 CYP1B1; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis; D004268:DNA-Binding Proteins; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D015603:Keratinocytes / Q000187:drug effects*; D051379:Mice; D018632:Mice, Inbred SENCAR; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D018336:Receptors, Aryl Hydrocarbon / Q000302:isolation & purification / Q000378:metabolism; D012867:Skin / Q000166:cytology / Q000187:drug effects*; D014157:Transcription Factors / Q000302:isolation & purification; D014158:Transcription, Genetic
chemical_list: D000444:Aldehyde Dehydrogenase; D001189:Aryl Hydrocarbon Hydroxylases; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D016895:Culture Media, Serum-Free; D019363:Cytochrome P-450 CYP1A1; D065633:Cytochrome P-450 CYP1B1; D003577:Cytochrome P-450 Enzyme System; D004268:DNA-Binding Proteins; D000072317:Polychlorinated Dibenzodioxins; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon; D014157:Transcription Factors; C497397:Arnt protein, mouse; C585498:Cyp1b1 protein, mouse; C105543:Aldh3a1 protein, mouse