MTF-1是具有調控金屬硫蛋白基因表現的轉錄因子，在MTF-1 N端的DNA結合區域是由六個連續排列的鋅指區域所構成，而其C端的轉錄活化區域則分別由acidic、proline-rich、serine/threonine-rich三個區域所構成。在本篇的研究當中，我們利用大腸桿菌表現系統，即BL21（DE3）菌株與pET28a載體，嘗試將mMTF-1 N端1-377含有六個鋅指區域的片段蛋白質（pMTF-1）表現出來。在表現的過程當中，我們發現當菌液培養在37℃時，會使得pMTF-1表現在insoluble fraction，若要增加pMTF-1溶解度則必須以16℃的低溫來表現蛋白質。利用鎳金屬親合管柱的初步純化後，再以膠體過濾層析法進一步分離pMTF-1。我們藉由EMSA確認純化出的pMTF-1與DNA之間結合的情形，結果發現pMTF-1於純化後會喪失其與DNA結合的活性，然而當我們外加CHO K1細胞萃取液時，即可回復其與DNA結合的能力，並且其與DNA結合之強度與CHO K1細胞所表現之全長mMTF-1一致。總結上述，在此我們建立了表現以及純化pMTF-1的系統。

MTF-1（metal-regulatory transcription factor-1）is a constitutively expressed protein that regulates metallothionein gene expression. The MTF-1 contains six zinc finger structures at the N-terminal region and an activation domain at C-terminus. In this work, we tried to express the His-tagged full length and truncated mMTF-1（pMTF-1）which contains six zinc fingers in E.coli expression system. We found that expressing of pMTF-1 at 16℃ improved the solubility of the protein. After eluting from nickel column, we used gel filtration to further purify the pMTF-1. We investigated the DNA binding activity of pMTF-1 by electrophoresis mobility shift assay. Notably, the DNA binding activity of pMTF-1 was absent after the purification. However the DNA binding activity recovered when incubating pMTF-1 with CHO K1 cell extracts. In conclusion, we develop the expression and purification system of pMTF-1.

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