title: Demethylation in the 5'-flanking region of mouse cellular retinoic acid binding protein-I gene is associated with its high level of expression in mouse embryos and facilitates its induction by retinoic acid in P19 embryonal carcinoma cells.
abstract: The mouse cellular retinoic acid binding protein-I (CRABP-I) gene is specifically up-regulated by retinoic acid (RA) in P19 mouse embryonal carcinoma cells, and its expression in animals is spatially and temporally restricted to RA-sensitive tissues during embryonic development. This study demonstrates that, in adult mouse tissues and P19 cells where the expression of CRABP-I is detected at the basal level, the 5'-flanking region of the CRABP-I gene is hypermethylated at the C residues of all the Hpa II sites. Conversely, in mouse embryos during early stages of development when the expression of CRABP-I gene is detected at a much higher level, this region is demethylated at these Hpa II sites. In P19, enhancement on the RA-induced up-regulation of CRABP-I can be observed in cells treated with 5-azacytidine (5-AzaC) in conjunction with RA, where partial demethylation in the 5'-flanking region of CRABP-I gene is observed. Nuclear run-on experiments indicate that increased message levels of CRABP-I in P19 cells can be accounted for, at least partially, by increases in its transcription rates. The induction of retinoic acid receptor (RAR) beta by RA can also be enhanced by 5-AzaC, but to a much lesser degree. In contrast, all the Hpa II sites in the structural gene portion, at least in the first two exons, are fully demethylated at the C residues.
authors.affiliation: Department of Pharmacology, University of Minnesota Medical School, Minneapolis 55455.
authors.forename: L N
authors.initials: LN
authors.lastname: Wei
authors.forename: C H
authors.initials: CH
authors.lastname: Lee
mesh_terms: D000818:Animals; D001374:Azacitidine / Q000494:pharmacology; D001483:Base Sequence; D018236:Carcinoma, Embryonal / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D019003:Deoxyribonuclease HpaII; D015252:Deoxyribonucleases, Type II Site-Specific; D005314:Embryonic and Fetal Development / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D008745:Methylation; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis; D018168:Receptors, Retinoic Acid / Q000235:genetics*; D015183:Restriction Mapping; D014158:Transcription, Genetic / Q000187:drug effects; D014212:Tretinoin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D012333:RNA, Messenger; D018168:Receptors, Retinoic Acid; C082927:retinoic acid binding protein I, cellular; D014212:Tretinoin; D004247:DNA; D019003:Deoxyribonuclease HpaII; D015252:Deoxyribonucleases, Type II Site-Specific; D001374:Azacitidine