Peterson M G, Hannan F, Mercer J F
Murdoch Institute, Royal Children's Hospital, Parkville, Victoria, Australia.
Eur J Biochem. 1988 Jun 1;174(2):417-24. doi: 10.1111/j.1432-1033.1988.tb14114.x.
Southern blot analysis of the sheep genome revealed a metallothionein gene family with at least nine members. Two overlapping cosmid clones spanning approximately 67 kb and containing five metallothionein genes have been isolated. DNA sequence analysis reveals that one of these is a metallothionein II variant, three are metallothionein I variants and one is a truncated metallothionein pseudogene containing only the first exon. The predicted amino acid sequence was compared with previously reported amino acid composition data of sheep metallothioneins [Whanger, P. D., Oh, S.-H. & Deagen, J. T. (1981) J. Nutr. 111, 1207-1215], and this suggests that we have isolated the genes encoding the major protein isoforms found in the sheep liver. The promoter regions of these genes contain many conserved elements, among them metal-regulatory elements and putative glucocorticoid-responsive elements. However, there are a number of differences between these genes in the arrangement of these elements. Sequence comparisons indicate that the multiple metallothionein I genes and the pseudogene appear to have resulted from sequential duplication events, and a larger cluster of metallothionein I genes may have been disrupted leading to the formation of the pseudogene.
对绵羊基因组的Southern印迹分析显示存在一个至少有九个成员的金属硫蛋白基因家族。已分离出两个重叠的黏粒克隆，其跨度约为67 kb，包含五个金属硫蛋白基因。DNA序列分析表明，其中一个是金属硫蛋白II变体，三个是金属硫蛋白I变体，还有一个是仅包含第一个外显子的截短金属硫蛋白假基因。将预测的氨基酸序列与先前报道的绵羊金属硫蛋白的氨基酸组成数据进行了比较[Whanger, P. D., Oh, S.-H. & Deagen, J. T. (1981) J. Nutr. 111, 1207 - 1215]，这表明我们已经分离出了编码绵羊肝脏中主要蛋白质异构体的基因。这些基因的启动子区域包含许多保守元件，其中包括金属调节元件和假定的糖皮质激素反应元件。然而，这些基因在这些元件的排列上存在一些差异。序列比较表明，多个金属硫蛋白I基因和假基因似乎是由连续的复制事件产生的，并且一个更大的金属硫蛋白I基因簇可能已经被破坏，导致了假基因的形成。
