Differential expression of four linked XXXX metallothionein genes.

@entity742 @entity73344 @entity219 @entity3409 @entity41771 @entity619 @entity920 @entity73343
Regulation of the closely linked endogenous @entity742 @entity73343 , MT-Ib, @entity73344 and @entity41771 genes by heavy metals and @entity619 was studied in cultured @entity742 fibroblasts. Only @entity41771 mRNA was detectable before addition of any inducer. Addition of @entity920 , @entity219 or @entity3409 salts to the culture medium increased the level of each mRNA; however, the magnitude of this response varied greatly between the four metallothionein genes. Following induction, levels of @entity73343 mRNA were the highest, followed by @entity41771 and @entity73344 mRNAs. The MT-Ib mRNA was only present at low levels. @entity219 and @entity3409 were found to be the most effective inducers of each gene. The maximal response of the sMT-Ia, Ib and II genes to @entity920 was only 30% of @entity219 and @entity3409 . The sMT-Ic gene responded very weakly to @entity920 , less than 5% of the levels achieved with @entity219 . Only the @entity41771 mRNA increased in response to @entity619 . In the liver of @entity742 on normal diets, the levels of @entity73343 , Ic and II mRNAs were found to be unexpectedly high and comparable to induced levels in fibroblasts.
