García Raúl, Bermejo Clara, Grau Cecilia, Pérez Rosa, Rodríguez-Peña Jose Manuel, Francois Jean, Nombela César, Arroyo Javier
Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain.
J Biol Chem. 2004 Apr 9;279(15):15183-95. doi: 10.1074/jbc.M312954200. Epub 2004 Jan 21.
In the yeast Saccharomyces cerevisiae, environmental stress conditions that damage the cell wall lead to activation of the so-called "compensatory mechanism," aimed at preserving cell integrity through a remodeling of this extracellular matrix. Here we used DNA microarrays to investigate the molecular basis of this response to two agents that induce transient cell wall damage; namely Congo Red and Zymolyase. Treatment of the cells with these two agents elicited the up-regulation of 132 and 101 genes respectively, the main functional groups among them being involved in cell wall construction and metabolism. The main response does not occur until hours after exposure to the cell wall-perturbing agent. In some cases, this response was transient, but more sustained in others, especially in the case of the genes involved in cell wall remodeling. Clustering of these data together with those from the response to constitutive cell wall damage, revealed the existence of a cluster of co-regulated genes that was strongly induced under all conditions assayed. Those genes induced by cell wall damage showed an enrichment in DNA binding motifs for Rlm1p, Crz1p, SBF (Swi4p/Swi6p), Msn2p/Msn4p, Ste12p, and Tec1p transcription factors, suggesting a complex regulation of this response together with the possible involvement of several signaling pathways. With the exception of PHO89 and FKS2, none of the genes induced by Congo Red was up-regulated in a slt2 strain. Moreover, characterization of the transcriptional response to Congo Red in a rlm1 mutant strain revealed that only a few genes (i.e. PHO89, FKS2, YLR042C, and CHA1) were induced at least partially independently of the transcription factor Rlm1p, the rest being totally dependent on this transcription factor for their activation. Our findings consistently demonstrate that the cell integrity signaling pathway regulates the cell wall damage compensatory response, mainly through transcriptional activation mediated by Rlm1p.
在酿酒酵母中，破坏细胞壁的环境应激条件会导致所谓“补偿机制”的激活，该机制旨在通过重塑这种细胞外基质来维持细胞完整性。在这里，我们使用DNA微阵列来研究对两种诱导短暂细胞壁损伤的试剂的这种反应的分子基础；即刚果红和溶菌酶。用这两种试剂处理细胞分别引起132个和101个基因的上调，其中主要功能组参与细胞壁的构建和代谢。主要反应直到暴露于细胞壁干扰剂数小时后才发生。在某些情况下，这种反应是短暂的，但在其他情况下更持久，特别是在参与细胞壁重塑的基因中。将这些数据与对组成性细胞壁损伤反应的数据聚类在一起，揭示了在所有检测条件下都强烈诱导的一组共同调控基因的存在。那些由细胞壁损伤诱导的基因在Rlm1p、Crz1p、SBF（Swi4p/Swi6p）、Msn2p/Msn4p、Ste12p和Tec1p转录因子的DNA结合基序中富集，这表明这种反应受到复杂调控，并且可能涉及多种信号通路。除了PHO89和FKS2外，刚果红诱导的基因在slt2菌株中均未上调。此外，对rlm1突变菌株中刚果红转录反应的表征表明，只有少数基因（即PHO89、FKS2、YLR042C和CHA1）至少部分独立于转录因子Rlm1p被诱导，其余基因的激活完全依赖于该转录因子。我们的研究结果一致表明，细胞完整性信号通路主要通过Rlm1p介导的转录激活来调节细胞壁损伤补偿反应。
