A widespread transposable element masks expression of a yeast copper transport gene
A widespread transposable element masks expression of a yeast copper transport gene
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DOI：
10.1101/gad.10.15.1917
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发表时间：
1996-08-01
影响因子：
10.5
通讯作者：
Thiele, DJ
中科院分区：
文献类型：
--
作者：
Knight, SAB;Labbe, S;Thiele, DJ
微量元素铜（Cu）是细胞生长所必需的。在这篇报道中，我们描述了酵母中一个由CTR3基因编码的高亲和力铜转运机制的新组分的鉴定。Ctr3p是一种小的细胞内富含半胱氨酸的整体膜蛋白，对缺乏CTR1 （Cu转运蛋白1）基因的菌株恢复高亲和力的Cu摄取、Cu、Zn超氧化物歧化酶活性、亚铁转运和呼吸能力。在大多数常用的酿酒酵母实验室菌株中，插入Ty2转座子使CTR3启动子与转录起始位点分离6kb，从而消除了CTR3的表达。在CTR3位点没有Ty2转座子的菌株中，CTR3的表达被铜抑制，并被铜饥饿激活。在这些菌株中，需要CTR1和CTR3灭活才能产生致死的缺铜表型。尽管Ctr1p和Ctr3p在铜运输中可以独立发挥作用，但在铜限制条件下，这两种蛋白的表达提供了最大的铜摄取和生长速度。这些结果强调了移动DNA元件在基因功能改变和表型变异中的重要性。
The trace element copper (Cu) is essential for cell growth. In this report we describe the identification of a new component of the high-affinity Cu transport machinery in yeast, encoded by the CTR3 gene. Ctr3p is a small intracellular cysteine-rich integral membrane protein that restores high-affinity Cu uptake, Cu, Zn superoxide dismutase activity, ferrous iron transport, and respiratory proficiency to strains lacking the CTR1 (Cu transporter 1) gene. In most commonly used Saccharomyces cerevisiae laboratory strains, expression of CTR3 is abolished by a Ty2 transposon insertion that separates the CTR3 promoter from the transcriptional start sites by 6 kb. In strains that do not possess a Ty2 transposon at the CTR3 locus, expression of CTR3 is repressed by copper and activated by copper starvation. In such strains inactivation of both CTR1 and CTR3 is required to generate lethal copper-deficient phenotypes. Although Ctr1p and Ctr3p can function independently in copper transport, the expression of both proteins provides maximal copper uptake and growth rate under copper-limiting conditions. These results underscore the importance of mobile DNA elements in the alteration of gene function and phenotypic variation.