The DAD1 (defender against apoptotic cell death) gene is a negative regulator of programmed cell death. It plays important roles in plant growth, development, environmental adaptation, and aging. We examined whether and how the expression of DAD1 gene is affected by the promoter changes in the allotetraploid upland cotton (Gossypium hirsutum L.). We compared the expression status of the genes in the leaves of an elite cultivar and a wild variety of G. hirsutum, and cloned and analyzed a 1.3-kb promoter region of the genes in two cotton types. Results revealed that the expression of a subgenomic homoeolog of DAD1 (DAD1 _At ) was significantly upregulated in leaves of the cultivated cotton when compared with that in a wild cotton. In addition, we identified 18 variations, including 14 single nucleotide polymorphisms and four indels between the promoters of the two cotton types. We detected at least 10 of 18 variations in the promoters related to possible cis-regulatory elements. Further transient tobacco assays using heterogeneous DAD1 _At promoter::GUS fusion showed that the activity of the DAD1 _At promoter in the cultivated cotton was stronger than that in the wild cotton, which suggested a dynamic change in the DAD1 _At promoter during genetic divergence of the two cottons. This study provides an example of how gene expression could be affected by specific changes in the gene promoter.

中文翻译：

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抗凋亡细胞死亡基因启动子的变化影响其在陆地棉中的表达

所述DAD1（对凋亡细胞死亡的后卫）基因是程序性细胞死亡的负调控因子。它在植物生长、发育、环境适应和衰老中起着重要作用。我们检查了DAD1基因的表达是否以及如何受异源四倍体陆地棉（Gossypium hirsutum L.）中启动子变化的影响。我们比较了一个优良品种和一个野生品种G. hirsutum叶片中基因的表达状态，并克隆和分析了两种棉花类型中基因的 1.3-kb 启动子区域。结果表明，DAD1的亚基因组同源物（DAD1 _At ) 与野生棉花相比，在栽培棉花的叶子中显着上调。此外，我们确定了 18 个变异，包括 14 个单核苷酸多态性和两种棉花类型启动子之间的 4 个插入缺失。我们在与可能的顺式调节元件相关的启动子中检测到至少 18 个变异中的 10 个。使用非均相进一步瞬态烟草测定DAD1 _在启动子:: GUS融合表明，活性DAD1_在在栽培棉花启动子在野生棉花，这表明在动态变化较强DAD1_在 两种棉花遗传分化过程中的启动子。这项研究提供了一个例子，说明基因启动子的特定变化如何影响基因表达。