The genotoxic carcinogen chromium(VI) alters the metal-inducible expression but not the basal expression of the metallothionein gene in vivo.
The ability of the carcinogen chromium(VI) to affect the basal and zinc-inducible expression of liver metallothionein was examined in 14- and 18-day chicken embryos in vivo. Metallothionein expression varied with the stage of embryo development, with basal steady-state mRNA levels being approximately three times lower in livers of 18-day versus 14-day chicken embryos. Chromium(VI) treatment had no effect on the basal steady-state levels of metallothionein mRNA and protein in either 14- or 18-day chicken embryo liver. Treatment of 14-day embryos with zinc(II) resulted in a 3- to 5-fold increase in steady-state levels of metallothionein mRNA in liver. Pre-treatment of 14-day embryos with chromium(VI) inhibited the zinc(II)-induced increase in steady-state levels of metallothionein mRNA and protein in liver by 30-50%. In contrast, chromium(VI) and/or zinc(II) treatments had no effect on steady-state levels of beta-actin mRNA.
Alcedo
J A
JA
Department of Biochemistry, Dartmouth Medical School, Hanover, NH.
Misra
M
M
Hamilton
J W
JW
Wetterhahn
K E
KE
D000818:Animals; D001483:Base Sequence; D002273:Carcinogens / Q000633:toxicity*; D002642:Chick Embryo; D002645:Chickens; D002857:Chromium / Q000633:toxicity*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D005984:Glutethimide / Q000494:pharmacology; D008668:Metallothionein / Q000235:genetics*; D008670:Metals / Q000494:pharmacology*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics
D002273:Carcinogens; D008670:Metals; D012333:RNA, Messenger; D002857:Chromium; D008668:Metallothionein; D005984:Glutethimide