Low temperature (23 degrees C) increases expression of biofilm-, cold-shock- and RpoS-dependent genes in Escherichia coli K-12.
Low temperature (23 degrees C) increases expression of biofilm-, cold-shock- and RpoS-dependent genes in Escherichia coli K-12.
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低温（23 摄氏度）会增加大肠杆菌 K-12 中生物膜、冷休克和 RpoS 依赖性基因的表达。
DOI：
10.1099/mic.0.2007/012021-0
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
Young,Sarah
中科院分区：
文献类型：
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作者：
White-Ziegler,ChristineA;Um,Suzin;Pérez,NatalieM;Berns,AbbyL;Malhowski,AmyJ;Young,Sarah
温度是调节大肠杆菌和其他细菌基因表达的一个线索。使用DNA微阵列，我们鉴定了297个基因，其表达在23 °C下比在37 °C下增加。 coliK-12。在这些基因中，122个是Rpos控制的，证实了全基因组模型，即低温是触发一般应激反应的主要线索。在23 °C下表达的几个基因与冷休克反应重叠，这表明用于适应温度突然变化的策略也介导了23 °C下的长期生长。 另一类基因在23 °C下更高表达与生物膜发育相关，暗示温度是影响该发育途径的重要线索。 在测试的一组候选基因中，发现生物膜基因（adrA、bolA、mlrA、nhaR、csgA、yceP/bssS）和冷休克基因（otsA、yceP/bssS）在23 °C下的转录依赖于RpoS和DsrA。 相比之下，三个基因（ycgZ，dpsandymgB）的转录部分或完全独立于这些调控因子，这表明存在另一种温度调节机制，可在23 °C下增加基因表达。 与37 °C相比，在23 °C下增加的表达在测试的各种培养基中保留了大多数基因，支持这种线索在适应变化的环境中的相对重要性。 RpoS依赖性基因A和RpoS非依赖性基因B在从37 °C转移到23 °C后1小时内表现出表达水平增加，表明对这种环境线索的快速反应。 尽管许多RpoS依赖性基因的基因表达发生了变化，但评估23 °C下生长速率和4 °C下生存力的实验并未证明rpoS：：Tn 10 ordsrA：：catmutant菌株与野生型菌株相比存在显著损害。 生物膜的形成在低温下是有利的，在23 °C下，在两种therpoS：：Tn 10和dsrA：：catmutants中中度受损，这表明由这些调节因子控制的基因在23 °C下的最佳生物膜形成中起着必要的作用。 总之，我们的数据表明，大量基因在23 °C下表达增加，以全面响应这种环境变化，并且至少有两种温度调节途径参与协调这种响应-RpoS/DsrA途径和独立于这些调节剂的替代温度调节途径。
Temperature serves as a cue to regulate gene expression inEscherichia coliand other bacteria. Using DNA microarrays, we identified 297 genes whose expression is increased at 23 °C compared to 37 °C inE. coliK-12. Of these genes, 122 are RpoS-controlled, confirming genome-wide the model that low temperature serves as a primary cue to trigger the general stress response. Several genes expressed at 23 °C overlap with the cold-shock response, suggesting that strategies used to adapt to sudden shifts in temperature also mediate long-term growth at 23 °C. Another category of genes more highly expressed at 23 °C are associated with biofilm development, implicating temperature as an important cue influencing this developmental pathway. In a candidate set of genes tested, the biofilm genes (adrA,bolA,mlrA,nhaR,csgA,yceP/bssS)and cold-shock genes (otsA,yceP/bssS)were found to be RpoS- and DsrA-dependent for their transcription at 23 °C. In contrast, transcription of three genes (ycgZ,dpsandymgB) was either partially or fully independent of these regulators, signifying there is an alternative thermoregulatory mechanism(s) that increases gene expression at 23 °C. Increased expression at 23 °C compared to 37 °C is retained in various media tested for most of the genes, supporting the relative importance of this cue in adaptation to changing environments. Both the RpoS-dependent geneotsAand the RpoS-independent geneymgBdemonstrated increased expression levels within 1 h after a shift from 37 to 23 °C, indicating a rapid response to this environmental cue. Despite changes in gene expression for many RpoS-dependent genes, experiments assessing growth rate at 23 °C and viability at 4 °C did not demonstrate significant impairment inrpoS: : Tn10ordsrA: :catmutant strains in comparison to the wild-type strain. Biofilm formation was favoured at low temperature and is moderately impaired in both therpoS: : Tn10anddsrA: :catmutants at 23 °C, suggesting genes controlled by these regulators play a role necessary for optimal biofilm formation at 23 °C. Taken together, our data demonstrate that a large number of genes are increased in expression at 23 °C to globally respond to this environmental change and that at least two thermoregulatory pathways are involved in co-ordinating this response – the RpoS/DsrA pathway and an alternative thermoregulatory pathway, independent of these regulators.