Extensive divergence of yeast stress responses through transitions between induced and constitutive activation
Extensive divergence of yeast stress responses through transitions between induced and constitutive activation
复制标题
DOI：
10.1073/pnas.1113718108
复制
发表时间：
2011-10-04
影响因子：
11.1
通讯作者：
Struhl, Kevin
中科院分区：
文献类型：
--
作者：
Tirosh, Itay;Wong, Koon Ho;Struhl, Kevin
密切相关的物种在基因表达上表现出高度差异，但这些差异的功能意义尚不清楚。同样，酵母的应激反应通常涉及许多基因的差异表达，目前尚不清楚这些基因中有多少在功能上是重要的。为了解决这些问题，我们比较了四种酵母在不同生长条件下的表达程序，发现这些物种对胁迫的反应存在很大差异。在单个基因的基础上，大多数转录反应在任何一对物种中都不保守，并且在所有四个物种中都有非常有限的共同反应。我们提供的证据表明，应激反应中的许多进化变化要么通过(i)相关基因的反应来补偿，要么通过（ii）反应偏离的基因的基础表达水平的变化来补偿。因此，在某些物种中，压力相关基因往往在压力下被诱导，但在其他物种中，即使在没有压力的情况下，它们也会保持高水平，这表明在诱导激活和构成激活之间存在过渡。此外，大约15%的应激反应只针对四种物种中的一种，没有证据表明补偿效应或应激相关注释，这些可能反映了对应激反应不重要的偶然调节（即生物噪声）。频繁的代偿性变化和生物噪声可以解释不同的表达反应如何支持相似的生理反应。
Closely related species show a high degree of differences in gene expression, but the functional significance of these differences remains unclear. Similarly, stress responses in yeast typically involve differential expression of numerous genes, and it is unclear how many of these are functionally significant. To address these issues, we compared the expression programs of four yeast species under different growth conditions, and found that the response of these species to stress has diverged extensively. On an individual gene basis, most transcriptional responses are not conserved in any pair of species, and there are very limited common responses among all four species. We present evidence that many evolutionary changes in stress responses are compensated either (i) by the response of related genes or (ii) by changes in the basal expression levels of the genes whose responses have diverged. Thus, stress-related genes are often induced upon stress in some species but maintain high levels even in the absence of stress at other species, indicating a transition between induced and constitutive activation. In addition, similar to 15% of the stress responses are specific to only one of the four species, with no evidence for compensating effects or stress-related annotations, and these may reflect fortuitous regulation that is unimportant for the stress response (i. e., biological noise). Frequent compensatory changes and biological noise may explain how diverged expression responses support similar physiological responses.