Allele-specific assay reveals functional variation in the chalcone synthase promoter of Arabidiopsis thaliana that is compatible with neutral evolution
Allele-specific assay reveals functional variation in the chalcone synthase promoter of Arabidiopsis thaliana that is compatible with neutral evolution
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DOI：
10.1105/tpc.104.027839
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发表时间：
2005-03-01
期刊：
影响因子：
11.6
通讯作者：
Mitchell-Olds, T
中科院分区：
文献类型：
--
作者：
de Meaux, J;Goebel, U;Mitchell-Olds, T
启动子被认为在适应性进化中起着重要作用，但人们对物种内微进化过程发生的调控多样性知之甚少。为了研究基因启动子的进化变化潜力，我们研究了拟南芥查尔酮合酶（CHS）顺式调控区的核苷酸和功能变异。CHS是生物合成途径的分支点酶，其导致影响植物与其环境之间的相互作用的次级代谢产物的产生。我们发现，在基因间区域的核苷酸多样性，包括CHS启动子（PI = 0.003）是兼容的中性预期。为了定量的功能变化，特别是作为一个结果的顺式调节CHS mRNA水平，我们开发了一种测定使用F1个体，其中不同的启动子等位基因进行比较，在一个共同的反式调节背景。我们研究了功能顺式调节变化，在不同的刺激代表了各种CHS转录环境（黑暗，光明，昆虫喂养）。我们观察到广泛的功能变异，其中一些似乎是独立的反式调节背景。功能和核苷酸多样性的比较表明，一个候选点突变，可以解释顺式调节光响应的差异。我们的研究结果表明，启动子的功能变化可以从几个突变，指向启动子区域作为一个基本的决定因素的功能遗传变异。
Promoters are thought to play a major role in adaptive evolution, yet little is known about the regulatory diversity within species, where microevolutionary processes take place. To investigate the potential for evolutionary change in the promoter of a gene, we examined nucleotide and functional variation of the Chalcone Synthase (CHS) cis-regulatory region in Arabidopsis thaliana. CHS is the branch point enzyme of a biosynthetic pathway that leads to the production of secondary metabolites influencing the interaction between the plant and its environment. We found that nucleotide diversity in the intergenic region encompassing the CHS promoter (pi = 0.003) is compatible with neutral expectations. To quantify functional variation specifically as a result of cis-regulation of CHS mRNA levels, we developed an assay using F1 individuals in which distinct promoter alleles are compared within a common trans-regulatory background. We examined functional cis-regulatory variation in response to different stimuli representing a variety of CHS transcriptional environments (dark, light, and insect feeding). We observed extensive functional variation, some of which appeared to be independent of the trans- regulatory background. Comparison of functional and nucleotide diversity suggested a candidate point mutation that may explain cis-regulatory differences in light response. Our results indicate that functional changes in promoters can arise from a few mutations, pointing to promoter regions as a fundamental determinant of functional genetic variation.