Peterson M G, Mercer J F
Eur J Biochem. 1986 Nov 3;160(3):579-85. doi: 10.1111/j.1432-1033.1986.tb10077.x.
Screening of a sheep genomic lambda library with a sheep metallothionein-I cDNA clone resulted in the isolation of a 13,200-base-pair fragment containing a metallothionein gene which DNA sequence analysis identified as the gene encoding the cloned cDNA. The two introns occur at identical positions to those in other mammalian metallothioneins but are considerably larger. The first intron contains a DNA element that is present in a related but not identical form in many places in the sheep genome. Comparison of the promoter sequences of this gene (sMT-Ia) with the promoters of metallothionein genes from other species identified a number of conserved regions which may be important in the regulation of this gene by heavy metals, glucocorticoids and alpha-interferon. In sheep fibroblasts, the levels of sMT-Ia mRNA was found to be maximally elevated (95-fold) in the presence of zinc or cadmium and elevated 30-fold in the presence of copper. Dexamethasone had no effect upon mRNA levels. Thus this gene shows a pattern of regulation similar to the human MT-If gene, but distinct from the other human and mouse metallothionein genes so far reported.
用绵羊金属硫蛋白 -I cDNA克隆筛选绵羊基因组λ文库，得到一个13200碱基对的片段，其中包含一个金属硫蛋白基因，DNA序列分析确定该基因就是编码克隆cDNA的基因。这两个内含子的位置与其他哺乳动物金属硫蛋白中的内含子位置相同，但要长得多。第一个内含子含有一个DNA元件，该元件以相关但不完全相同的形式存在于绵羊基因组的许多位置。将该基因（sMT -Ia）的启动子序列与其他物种的金属硫蛋白基因启动子进行比较，发现了一些保守区域，这些区域可能在重金属、糖皮质激素和α -干扰素对该基因的调控中起重要作用。在绵羊成纤维细胞中，发现锌或镉存在时sMT -Ia mRNA水平最高可升高95倍，铜存在时升高30倍。地塞米松对mRNA水平没有影响。因此，该基因显示出与人类MT -If基因相似的调控模式，但与迄今为止报道的其他人类和小鼠金属硫蛋白基因不同。
