title: Correlation of dysfunction of nonmuscle myosin IIA with increased induction of Cyp1a1 in Hepa-1 cells.
abstract: The aryl hydrocarbon receptor (AhR) is one of the best known ligand-activated transcription factors and it induces Cyp1a1 transcription by binding with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Recent focus has been on the relationship of AhR with signaling pathways that modulate cell shape and migration. In nonmuscle cells, nonmuscle myosin II is one of the key determinants of cell morphology, but it has not been investigated whether its function is related to Cyp1a1 induction. In this study, we observed that (-)-blebbistatin, which is a specific inhibitor of nonmuscle myosin II, increased the level of CYP1A1-mRNA in Hepa-1 cells. Comparison of (-)-blebbistatin with (+)-blebbistatin, which is an inactive enantiomer, indicated that the increase of CYP1A1-mRNA was due to nonmuscle myosin II inhibition. Subsequent knockdown experiments observed that reduction of nonmuscle myosin IIA, which is only an isoform of nonmuscle myosin II expressed in Hepa-1 cells, was related to the enhancement of TCDD-dependent Cyp1a1 induction. Moreover, chromatin immunoprecipitation assay indicated that the increase of Cyp1a1 induction was the result of transcriptional activation due to increased binding of AhR and RNA polymerase II to the enhancer and proximal promoter regions of Cyp1a1, respectively. These findings provide a new insight into the correlation between the function of nonmuscle myosin II and gene induction.
authors.affiliation: Science of Bioresources, United Graduate School of Agricultural Science, Iwate University, Morioka 020-8551, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ebina
authors.forename: Masahiko
authors.initials: M
authors.lastname: Shibazaki
authors.forename: Kyoko
authors.initials: K
authors.lastname: Kudo
authors.forename: Shuya
authors.initials: S
authors.lastname: Kasai
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kikuchi
mesh_terms: D000818:Animals; D019363:Cytochrome P-450 CYP1A1 / Q000096:biosynthesis* / Q000235:genetics; D004790:Enzyme Induction / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D055785:Gene Knockdown Techniques; D006576:Heterocyclic Compounds, 4 or More Rings / Q000494:pharmacology; D051379:Mice; D041681:NIH 3T3 Cells; D024507:Nonmuscle Myosin Type IIA / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D020033:Protein Isoforms / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D006576:Heterocyclic Compounds, 4 or More Rings; D000072317:Polychlorinated Dibenzodioxins; D020033:Protein Isoforms; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon; C472645:blebbistatin; D019363:Cytochrome P-450 CYP1A1; D012319:RNA Polymerase II; D024507:Nonmuscle Myosin Type IIA