Knockout of 'metal-responsive transcription factor' MTF-1 in Drosophila by homologous recombination reveals its central role in heavy metal homeostasis
Knockout of 'metal-responsive transcription factor' MTF-1 in Drosophila by homologous recombination reveals its central role in heavy metal homeostasis
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DOI：
10.1093/emboj/cdg012
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发表时间：
2003-01-02
期刊：
影响因子：
11.4
通讯作者：
Schaffner, W
中科院分区：
文献类型：
--
作者：
Egli, D;Selvaraj, A;Schaffner, W
金属应答转录因子-1（Metal-responsive transcription factor-1，MTF-1）是一种锌指蛋白，在哺乳动物和昆虫中均存在。在小鼠中，它会激活金属硫蛋白基因和其他靶基因，以响应多种细胞应激条件，特别是重金属负荷。小鼠中MTF-1的敲除具有胚胎致死表型，伴有肝脏变性。在这里，我们描述了在果蝇的MTF-1基因的同源重组有针对性的破坏。与小鼠的情况不同，果蝇中MTF-1的敲除不是致命的。苍蝇在实验室条件下存活良好，但对高浓度的铜，镉和锌敏感。果蝇金属硫蛋白基因MtnA（Mtn）和MtnB（Mto）的基础和金属诱导的表达，以及这里描述的两个新的金属硫蛋白基因MtnC和MtnD，在MTF-1突变体中被废除。出乎意料的是，MTF-1突变体幼虫不仅对铜负荷敏感，而且对铜消耗敏感。在MTF-1突变体中，铜耗竭阻止变态并显著延长幼虫发育/寿命，从正常的4-5天延长至多达32天，这可能反映了氧代谢受损的影响。这些发现扩展了MTF-1在重金属稳态控制中的作用。
'Metal-responsive transcription factor-1' (MTF-1), a zinc finger protein, is conserved from mammals to insects. In the mouse, it activates metallothionein genes and other target genes in response to several cell stress conditions, notably heavy metal load. The knockout of MTF-1 in the mouse has an embryonic lethal phenotype accompanied by liver degeneration. Here we describe the targeted disruption of the MTF-1 gene in Drosophila by homologous recombination. Unlike the situation in the mouse, knockout of MTF-1 in Drosophila is not lethal. Flies survive well under laboratory conditions but are sensitive to elevated concentrations of copper, cadmium and zinc. Basal and metal-induced expression of Drosophila metallothionein genes MtnA (Mtn) and MtnB (Mto), and of two new metallothionein genes described here, MtnC and MtnD, is abolished in MTF-1 mutants. Unexpectedly, MTF-1 mutant larvae are sensitive not only to copper load but also to copper depletion. In MTF-1 mutants, copper depletion prevents metamorphosis and dramatically extends larval development/lifespan from normally 4-5 days to as many as 32 days, possibly reflecting the effects of impaired oxygen metabolism. These findings expand the roles of MTF-1 in the control of heavy metal homeostasis.