title: 4S polycyclic aromatic hydrocarbon receptor (glycine N-methyltransferase) and the aryl hydrocarbon receptor nuclear translocator (hypoxia inducible factor-1β) interaction in Chinese hamster ovary and rat hepatoma cells: 4S PAH-R/ARNT hetero-oligomers?
abstract: Rat CYP1A1 promoter-luciferase, transiently transfected wild-type and 4S PAH receptor (glycine N-methyl transferase, GNMT)-transformed Chinese hamster ovary (CHO) cells were exposed to benzo[a]pyrene and assayed for luciferase activity as an indicator of CYP1A1 promoter activity. CHO cells transformed with the rat 4S PAH receptor/GNMT expression vector had twice the induction level of luciferase activity with respect to wild-type CHO cells in concert with previously published reports that the 4S PAH receptor/GNMT mediates benzo[a]pyrene induction of CYP1A1 gene expression. Lysates of GNMT-transformed CHO cells and wild-type H4IIE rat hepatoma cells exposed to benzo[a]pyrene were immuno-precipitated with anti-GNMT antibodies, separated by SDS-polyacrylamide gel electrophoresis and transferred to PVDF membrane for Western blot analysis with anti-aryl hydrocarbon receptor nuclear translocator (ARNT, HIF-1β) antibodies. Results of this analysis indicated that the 4S PAH receptor/GNMT forms a hetero-oligomer (dimer?) with ARNT/HIF-1β which dissociates in the presence of B[a]P. These observations further indicate the role of GNMT (which has been shown to be multifunctional) and B[a]P in the induction of CYP1A1 and also a potential role of GNMT in the modulation of hypoxia inducible factor-1 function with respect to the HIF-1β subunit (ARNT).
authors: University of Florida, Whitney Laboratory, 9505 Ocean Shore Blvd., St. Augustine, Florida 32080, USA. ksterling@whitney.ufl.edu
authors: Kenneth M
authors: KM
authors: Sterling
mesh_terms: D000818:Animals; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator / Q000235:genetics / Q000378:metabolism*; D001564:Benzo(a)pyrene / Q000494:pharmacology; D016466:CHO Cells; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D006224:Cricetinae; D003412:Cricetulus; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000235:genetics; D050938:Glycine N-Methyltransferase / Q000235:genetics / Q000378:metabolism*; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D051381:Rats
chemical_list: D009363:Neoplasm Proteins; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D001564:Benzo(a)pyrene; D019363:Cytochrome P-450 CYP1A1; D050938:Glycine N-Methyltransferase; C494512:Gnmt protein, rat