Department of Biotechnology, Faculty of Life Science and Biotechnology, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan.
J Bacteriol. 2011 May;193(10):2388-95. doi: 10.1128/JB.00016-11. Epub 2011 Mar 11.
The Bacillus subtilis fadR regulon involved in fatty acid degradation comprises five operons, lcfA-fadR-fadB-etfB-etfA, lcfB, fadN-fadA-fadE, fadH-fadG, and fadF-acdA-rpoE. Since the lcfA-fadRB-etfBA, lcfB, and fadNAE operons, whose gene products directly participate in the β-oxidation cycle, had been found to be probably catabolite repressed upon genome-wide transcript analysis, we performed Northern blotting, which indicated that they are clearly under CcpA-dependent catabolite repression. So, we searched for catabolite-responsive elements (cre's) to which the complex of CcpA and P-Ser-HPr binds to exert catabolite repression by means of a web-based cis-element search in the B. subtilis genome using known cre sequences, which revealed the respective candidate cre sequences in the lcfA, lcfB, and fadN genes. DNA footprinting indicated that the complex actually interacted with these cre's in vitro. Deletion analysis of each cre using the lacZ fusions with the respective promoter regions of the three operons with and without it, indicated that these cre's are involved in the CcpA-dependent catabolite repression of the operons in vivo.
枯草芽孢杆菌 fadR 调控基因参与脂肪酸降解，包括五个操纵子：lcfA-fadR-fadB-etfB-etfA、lcfB、fadN-fadA-fadE、fadH-fadG 和 fadF-acdA-rpoE。由于 lcfA-fadRB-etfBA、lcfB 和 fadNAE 操纵子的基因产物直接参与β-氧化循环，在全基因组转录分析中发现可能受到分解代谢物阻遏，我们进行了 Northern 印迹杂交，结果表明它们明显受到 CcpA 依赖的分解代谢物阻遏。因此，我们搜索了 catabolite-responsive elements (cre's)，CcpA 和 P-Ser-HPr 复合物结合到这些元件上，通过在枯草芽孢杆菌基因组中使用已知的 cre 序列进行基于网络的顺式元件搜索，发现了 lcfA、lcfB 和 fadN 基因中的相应候选 cre 序列。DNA 足迹分析表明，该复合物实际上在体外与这些 cre 相互作用。使用 lacZ 融合物对三个操纵子的每个 cre 进行缺失分析，无论是否存在它，都表明这些 cre 参与了体内操纵子的 CcpA 依赖的分解代谢物阻遏。
