Regulation of the Bacillus subtilis Divergent yetL and yetM Genes by a Transcriptional Repressor, YetL, in Response to Flavonoids
Regulation of the Bacillus subtilis Divergent yetL and yetM Genes by a Transcriptional Repressor, YetL, in Response to Flavonoids
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DOI：
10.1128/jb.00202-09
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发表时间：
2009-06-01
影响因子：
3.2
通讯作者：
Fujita, Yasutaro
中科院分区：
文献类型：
--
作者：
Hirooka, Kazutake;Danjo, Yusuke;Fujita, Yasutaro
DNA微阵列分析表明，转录的枯草芽孢杆菌yetM基因编码一个假定的黄素腺嘌呤二核苷酸依赖性单加氧酶被触发的某些类黄酮在培养过程中，并通过破坏的yetL基因在相反的方向位于上游的yetM，它编码一个假定的马尔家族转录调节。体外分析，包括DNA酶I足迹和凝胶阻滞分析，表明YetL特异性结合到不同的yetL和yetM启动子区域中的相应单个位点，对yetM区域具有更高的亲和力;前一区域与yetL的Shine-Dalgarno序列重叠，后一区域包含完美的18 bp回文序列（TAGTTAGGCGCCTAACTA）。体外凝胶阻滞和体内lacZ融合分析表明，一些黄酮类化合物，（山奈酚、芹菜素和毛地黄黄酮）有效抑制YetL与yetM顺式序列的结合，但槲皮素、高良姜素和白杨素不抑制这种结合，这意味着黄酮结构的B-环上的4-羟基对于这种抑制作用是不可缺少的，并且B-和C-环上的3-羟基的共存是可能的。环不允许拮抗YetL。
DNA microarray analysis revealed that transcription of the Bacillus subtilis yetM gene encoding a putative flavin adenine dinucleotide-dependent monooxygenase was triggered by certain flavonoids during culture and was derepressed by disruption of the yetL gene in the opposite orientation situated immediately upstream of yetM, which encodes a putative MarR family transcriptional regulator. In vitro analyses, including DNase I footprinting and gel retardation analysis, indicated that YetL binds specifically to corresponding single sites in the divergent yetL and yetM promoter regions, with higher affinity to the yetM region; the former region overlaps the Shine-Dalgarno sequence of yetL, and the latter region contains a perfect 18-bp palindromic sequence (TAGTTAGGCGCCTAACTA). In vitro gel retardation and in vivo lacZ fusion analyses indicated that some flavonoids (kaempferol, apigenin, and luteolin) effectively inhibit YetL binding to the yetM cis sequence, but quercetin, galangin, and chrysin do not inhibit this binding, implying that the 4-hydroxyl group on the B-ring of the flavone structure is indispensable for this inhibition and that the coexistence of the 3-hydroxyl groups on the B- and C-rings does not allow antagonism of YetL.