[Function comparison and evolution analysis of metallothionein gene MTT2 and MTT4 in Tetrahymena thermophila].
[Function comparison and evolution analysis of metallothionein gene MTT2 and MTT4 in Tetrahymena thermophila].
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DOI：
10.3724/sp.j.1141.2011.05476
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发表时间：
2011-10
期刊：
影响因子：
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通讯作者：
Yue Chang;Lifang Feng;Jie Xiong;W. Miao
中科院分区：
文献类型：
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作者：
Yue Chang;Lifang Feng;Jie Xiong;W. Miao
四膜虫具有较高的金属硫蛋白基因多态性。这些蛋白质亚型可分为7a和7b两个亚家族。用实时荧光定量聚合酶链式反应检测了嗜热四膜虫金属硫蛋白基因MTT2和MTT4在不同诱导剂汞、铜、镉、锌和H(2)O(2)作用下的表达水平。铜和汞对这两个基因的诱导效率最高，其次是汞。在镉、锌暴露后，它们的表达略有上调，但受H(2)O(2)的抑制。其表达模式与已报道的7a亚家族成员不同，但与7b亚家族成员的表达模式一致。然而，MTT4的诱导表达水平远高于MTT2，这可能是由于它们的上游调控元件(AP-1、MRE)的差异所致。在基因结构和功能上的高度相似性表明，MTT2和MTT4是遵循剂量平衡模型的最近基因复制产生的。
Tetrahymena has a high genetic polymorphism of metallothionein proteins. These protein isoforms can be divided into subfamilies 7a and 7b. We used real-time quantitative PCR to test the expression levels of Tetrahymena thermophila metallothionein genes MTT2 and MTT4 after exposure to different inducers, including Hg, Cu, Cd, Zn and H(2)O(2). Both genes were most efficiently induced by Cu and secondly by Hg. Their expression was slightly up-regulated after exposure to Cd and Zn, but down-regulated by H(2)O(2). The expression pattern differed from those reported in the 7a subfamily, but was consistent with 7b subfamily members. However, the induced expression level of MTT4 was much higher than that of MTT2, which might be due to differences in their upstream regulatory elements (AP-1, MRE). The high similarities in gene structures and functions indicate that MTT2 and MTT4 were generated by recent gene duplication following the dosage balance model.