title: Ultraviolet radiation-induced metallothionein-I gene activation is associated with extensive DNA demethylation.
abstract: Ultraviolet irradiation (UV) of cadmium-sensitive S49 mouse cells induces a large increase in cadmium-resistant variants. About 30%-40% of these variants make metallothionein (MT)-I mRNA while S49 cells do not. S49 cells contain two copies of the MT-I gene; both alleles are heavily methylated but can be conveniently distinguished by the methylation status of a single Hpa II site. In lines expressing MT-I, one allele becomes completely demethylated at all methylation-sensitive restriction sites examined over at least a 2.5 kb region spanning the MT-I gene. Activation of a quiescent gene by UV has implications for understanding the initiation of carcinogenesis.
mesh_terms: D000818:Animals; D002104:Cadmium / Q000494:pharmacology; D002460:Cell Line; D004247:DNA / Q000378:metabolism*; D004351:Drug Resistance / Q000528:radiation effects; D005786:Gene Expression Regulation / Q000528:radiation effects*; D005796:Genes; D008223:Lymphoma; D008668:Metallothionein / Q000235:genetics*; D008745:Methylation; D051379:Mice; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D015533:Transcriptional Activation; D014466:Ultraviolet Rays
chemical_list: D012333:RNA, Messenger; D002104:Cadmium; D004247:DNA; D008668:Metallothionein