Significance of consensus CYC‐binding sites found in the promoters of both ChCYC and ChRAD genes in Chirita heterotricha (Gesneriaceae)
Significance of consensus CYC‐binding sites found in the promoters of both ChCYC and ChRAD genes in Chirita heterotricha (Gesneriaceae)
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DOI：
10.1111/j.1759-6831.2010.00086.x
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发表时间：
2010-07
影响因子：
3.7
通讯作者：
Xia Yang;Hong Cui;Zu Yuan;Yin‐Zheng Wang
中科院分区：
文献类型：
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作者：
Xia Yang;Hong Cui;Zu Yuan;Yin‐Zheng Wang
摘要CYC样基因在真双子叶植物核心区的相应区域中持续表达，在控制花的背腹不对称性（左右对称性）方面具有广泛的保守性。为了了解CYC样基因的表达是如何在花发育过程中维持的，我们选择了异毛唇柱苣苔作为材料，并通过反向聚合酶链反应分离了CYC同源物ChCYC 1C和ChCYC 1D基因的启动子序列。进一步的启动子分析导致在每个启动子中鉴定出与金鱼草CYC蛋白的共有DNA结合位点相匹配的推定的顺式调节元件：ChCYC 1C的GGCCCCTC位于−165，ChCYC 1D的GGCCCC位于−163。这表明，这两个ChCYC 1C和ChCYC 1D基因可能已经演变成自动调节环，以维持其在发育中的花的表达。我们还分离了ChRAD基因的编码和启动子序列，ChRAD基因是金鱼草RAD的同源物。启动子分析表明，ChRAD基因启动子也含有一个推定的CYC结合位点（GGCCCAC在−134）。因此，ChRAD可能是ChCYC 1基因的直接靶点，这与金鱼草RAD相似。这些结果表明，在唇柱苣苔花的两侧对称的建立可能已经实现了CYC样基因的自动调节环的进化，这可能是伴随着RAD样基因的同时co-option到他们的监管网络。
Abstract CYC‐like genes are widely conserved in controlling floral dorsoventral asymmetry (zygomorphy) through persistent expression in corresponding domains in core eudicots. To understand how CYC‐like gene expression is maintained during flower development, we selected Chirita heterotricha as a material and isolated the promoter sequences of the ChCYC1C and ChCYC1D genes, homologs of CYC, by inverse polymerase chain reaction. Further promoter analyses led to the identification of a putative cis‐regulatory element in each promoter matching the consensus DNA binding site for Antirrhinum CYC protein: GGCCCCTC at −165 for ChCYC1C, and GGCCCCCC at −163 for ChCYC1D. This indicates that both the ChCYC1C and ChCYC1D genes have probably evolved autoregulatory loops to sustain their expression in developing flowers. We also isolated the coding and promoter sequences of the ChRAD gene, a homolog of Antirrhinum RAD. Promoter analysis showed that the ChRAD gene promoter also contained a putative CYC‐binding site (GGCCCAC at −134). Therefore, ChRAD is likely a direct target of the ChCYC1 genes, which is similar to Antirrhinum RAD. These results imply that the establishment of floral zygomorphy in Chirita may have been achieved by the evolution of an autoregulatory loop for CYC‐like genes, which was probably accompanied by simultaneous co‐option of the RAD‐like gene into their regulatory network.