In Lactobacillus plantarum, fructooligosaccharides (FOS) metabolism is controlled by both global and local regulatory mechanisms. Although catabolite control protein A has been identified as a global regulator of FOS metabolism, the functions of local regulators remain unclear. This study aimed to elucidate the roles of two local regulators, SacR1 and SacR2, in the regulation of FOS metabolism in L. plantarum both in vitro and in vivo. The inactivation of sacR1 and sacR2 affected the growth and production of metabolites for strains grown on FOS or glucose, respectively. A reverse transcription-quantitative PCR analysis of one wild-type and two mutant strains (ΔsacR1 and ΔsacR2) of L. plantarum identified SacR1 and SacR2 as repressors of genes relevant to FOS metabolism in the absence of FOS, and these genes could be induced or derepressed by the addition of FOS. The analysis predicted four potential transcription factor binding sites (TFBSs) in the putative promoter regions of two FOS-related clusters. The binding of SacR1 and SacR2 to these TFBSs both in vitro and in vivo was verified using electrophoretic mobility shift assays and chromatin immunoprecipitation, respectively. A consensus sequence of WNNNNNAACGNNTTNNNNNW was deduced for the TFBSs of SacR1 and SacR2. Our results identified SacR1 and SacR2 as local repressors for FOS metabolism in L. plantarum. The regulation is achieved by the binding of SacR1 and SacR2 to TFBSs in the promoter regions of FOS-related clusters. The results provide new insights into the complex network regulating oligosaccharide metabolism by lactic acid bacteria.

中文翻译：

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本地转录调节因子SacR1和SacR2充当植物乳杆菌中低聚果糖代谢的阻遏物。

在植物乳杆菌中，低聚果糖（FOS）的代谢受全局和局部调节机制的控制。尽管分解代谢物控制蛋白A已被确定为FOS代谢的整体调节剂，但局部调节剂的功能仍不清楚。这项研究旨在阐明两个局部调节因子SacR1和SacR2在体外和体内调节植物乳杆菌FOS代谢中的作用。sacR1和sacR2的失活分别影响在FOS或葡萄糖上生长的菌株的生长和代谢产物的产生。对植物乳杆菌的一种野生型和两种突变菌株（ΔsacR1和ΔsacR2）进行的逆转录定量PCR分析表明，在没有FOS的情况下，SacR1和SacR2是与FOS代谢相关的基因的阻遏物，并且通过添加FOS可以诱导或抑制这些基因。该分析预测了两个FOS相关簇的推定启动子区域中的四个潜在的转录因子结合位点（TFBS）。SacR1和SacR2与这些TFBS在体外和体内的结合分别使用电泳迁移率变动分析和染色质免疫沉淀法进行了验证。对SacR1和SacR2的TFBS推导了WNNNNNAACGNNTTNNNNNW的共有序列。我们的结果确定SacR1和SacR2是植物乳杆菌中FOS代谢的局部阻遏物。通过将SacR1和SacR2与FOS相关簇的启动子区域中的TFBS结合来实现调节。该结果为调节乳酸菌寡糖代谢的复杂网络提供了新的见解。该分析预测了两个FOS相关簇的推定启动子区域中的四个潜在的转录因子结合位点（TFBS）。SacR1和SacR2与这些TFBS在体外和体内的结合分别使用电泳迁移率变动分析法和染色质免疫沉淀法进行了验证。对SacR1和SacR2的TFBS推导了WNNNNNAACGNNTTNNNNNW的共有序列。我们的结果确定SacR1和SacR2为植物乳杆菌中FOS代谢的局部阻遏物。通过将SacR1和SacR2与FOS相关簇的启动子区域中的TFBS结合来实现调节。该结果为调节乳酸菌寡糖代谢的复杂网络提供了新的见解。该分析预测了两个FOS相关簇的推定启动子区域中的四个潜在的转录因子结合位点（TFBS）。SacR1和SacR2与这些TFBS在体外和体内的结合分别使用电泳迁移率变动分析法和染色质免疫沉淀法进行了验证。对SacR1和SacR2的TFBS推导了WNNNNNAACGNNTTNNNNNW的共有序列。我们的结果确定SacR1和SacR2为植物乳杆菌中FOS代谢的局部阻遏物。通过将SacR1和SacR2与FOS相关簇的启动子区域中的TFBS结合来实现调节。该结果为调节乳酸菌寡糖代谢的复杂网络提供了新的见解。SacR1和SacR2与这些TFBS在体外和体内的结合分别使用电泳迁移率变动分析法和染色质免疫沉淀法进行了验证。对SacR1和SacR2的TFBS推导了WNNNNNAACGNNTTNNNNNW的共有序列。我们的结果确定SacR1和SacR2为植物乳杆菌中FOS代谢的局部阻遏物。通过将SacR1和SacR2与FOS相关簇的启动子区域中的TFBS结合来实现调节。该结果为调节乳酸菌寡糖代谢的复杂网络提供了新的见解。SacR1和SacR2与这些TFBS在体外和体内的结合分别使用电泳迁移率变动分析法和染色质免疫沉淀法进行了验证。对SacR1和SacR2的TFBS推导了WNNNNNAACGNNTTNNNNNW的共有序列。我们的结果确定SacR1和SacR2为植物乳杆菌中FOS代谢的局部阻遏物。通过将SacR1和SacR2与FOS相关簇的启动子区域中的TFBS结合来实现调节。该结果为调节乳酸菌寡糖代谢的复杂网络提供了新的见解。通过将SacR1和SacR2与FOS相关簇的启动子区域中的TFBS结合来实现调节。该结果为调节乳酸菌寡糖代谢的复杂网络提供了新的见解。通过将SacR1和SacR2与FOS相关簇的启动子区域中的TFBS结合来实现调节。该结果为调节乳酸菌寡糖代谢的复杂网络提供了新的见解。