近日，國(guó)際著名雜志Gene在線(xiàn)刊登了韓國(guó)釜山國(guó)立大學(xué)研究人員的最新研究成果“AntR-mediated bidirectional activation of antA and antR,，anthranilate degradative genes in Pseudomonas aeruginosa”，文章中,，研究者揭示了轉(zhuǎn)錄調(diào)節(jié)因子AntR的雙向激活基因的作用。
雙向轉(zhuǎn)錄激活作用是基因表達(dá)的一種特定模式,。在細(xì)菌中,，轉(zhuǎn)錄調(diào)節(jié)作用可以被轉(zhuǎn)錄因子雙向調(diào)節(jié)，比如銅綠假單胞菌的群體感應(yīng)系統(tǒng)調(diào)節(jié)子LasR和QscR,，可以在結(jié)合到單一位點(diǎn)來(lái)同時(shí)激活兩個(gè)分開(kāi)的基因進(jìn)行雙向表達(dá),。
在這篇研究文章中， 作者Joon-Hee Lee揭示了鄰氨基苯甲酸鹽代謝相關(guān)轉(zhuǎn)錄激活子AntR可以對(duì)別的基因進(jìn)行雙向轉(zhuǎn)錄調(diào)節(jié)的作用,。
在銅綠假單胞菌中（P.aeruginosa）中,，antABC操縱子和基因antR分別位于染色體的不同位置（不相鄰，分開(kāi)的）,，研究者為了更好地理解AntR對(duì)antABC的轉(zhuǎn)錄調(diào)節(jié)作用,，他們繪制了轉(zhuǎn)錄起始位點(diǎn)以及AntR的轉(zhuǎn)錄調(diào)節(jié)元件antAp。通過(guò)研究,，研究者發(fā)現(xiàn)AntR可以激活兩個(gè)分開(kāi)的基因,，antA和antR，而且在antA和antR基因的間隔區(qū)域存在兩個(gè)AntR的效應(yīng)元件AREs(AntR responsive elements),。因此,，研究者表示這兩個(gè)AREs對(duì)于AntR有不同的親和力，而且對(duì)于不對(duì)稱(chēng)地雙向激活基因antA和antR的表達(dá)至關(guān)重要,。（生物谷：T.Shen編譯）
doi:10.1016/j.gene.2012.05.004
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AntR-mediatedbidirectionalactivation of antA and antR, anthranilatedegradativegenes in Pseudomonasaeruginosa
Soo-Kyoung Kim1, Su-Jin Im1, Doo-Hwan Yeom, Joon-Hee Lee,
Bidirectionalactivation of transcription is a peculiar regulation mode of gene expression. In this study, we show that genes involved in the metabolism of anthranilate, a precursor of biosynthesis of tryptophan and Pseudomonas quinolone signal (PQS) are regulated by this bidirectionalactivation of transcription. Anthranilate is degraded by anthranilate dioxygenase complex encoded by antABC operon, and AntR, a LysR-type regulator encoded by antR activates the transcription of antABC operon in the presence of anthranilate. In P. aeruginosa, antABC and antR are divergently located and AntR binds to the intergenic region between antA and antR to activate the antABC transcription. In this study, we determined the transcriptional start site of the antA promoter (antAp) and AntR-responsive elements (AREs) in P. aeruginosa. The upstream deletion analysis of antAp and in vitro gel shift assay with purified AntR showed that there are two AREs at − 194 to − 148 and − 88 to − 47 regions. We also found that AntR activates antR promoter (antRp) in the opposite direction and both AREs are important in the bidirectionalactivation of antAp and antRp. Two AREs have different binding affinities to AntR and the strength of transcriptional activation was dramatically asymmetric depending on the direction. We suggest that the different affinities of two AREs may explain the asymmetry of the bidirectionalactivation by AntR.
