Isolation of Cladonema Pax-B genes and studies of the DNA-binding properties of cnidarian Pax paired domains.
Isolation of Cladonema Pax-B genes and studies of the DNA-binding properties of cnidarian Pax paired domains.
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枝线虫 Pax-B 基因的分离和刺胞动物 Pax 配对结构域 DNA 结合特性的研究。
DOI：
10.1093/oxfordjournals.molbev.a003731
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发表时间：
2001
影响因子：
10.7
通讯作者：
Li,WH
中科院分区：
文献类型：
--
作者：
Sun,H;Dickinson,DP;Costello,J;Li,WH
Paxgenes 编码参与发育控制的核转录因子。它们含有一个保守的 DNA 结合域，即配对域。配对结构域的DNA结合特异性与Pax蛋白的基因调控功能直接相关。之前根据配对结构域的系统发育分析将Paxgenes分为五类。在这项研究中，我们发现并测序了来自加州克拉多尼玛（Cladonema californicum）（一种有眼睛的水母）的两个高度相似的刺胞动物Pax-B基因。为了了解本研究和之前的研究中分离出的 cnidarianPaxgenes 的功能，我们使用基于 PCR 的方法和电泳迁移率变动测定来表征由 cnidarian 配对结构域结合的共有 DNA 序列。获得的共有 DNA 序列与哺乳动物 Pax 蛋白结合的序列非常相似。已知共有序列的比较表明它们都是部分回文的，但这一特征在刺胞动物中最为突出，这表明祖先配对结构域结合的DNA序列可能是回文的。此外，刺胞动物配对结构域（如 Pax-2/5/8 的配对结构域）比其他配对结构域具有更广泛的结合特异性，这意味着 Pax-2/5/8 和 Pax-4/6 配对结构域的共同祖先也可能具有类似的广泛 DNA 结合特异性。迄今为止，在所检查的几个刺胞动物物种中尚未发现明确的Pax-6基因，这与Pax-6基因的后来起源一致，并提出了两种可能性：刺胞动物的Pax基因是多功能的并且控制两个或多个发育途径，包括眼睛发育，或者它们使用不依赖于Pax的途径来进行眼睛发育。这条途径是否确实存在并且是刺胞动物所独有的，或者它是否代表了后来 Pax-6 纳入其中的真正的主控制，仍有待确定。
Paxgenes encode nuclear transcription factors that are involved in developmental control. They contain a conserved DNA-binding domain, the paired domain. The DNA-binding specificity of paired domains is directly related to the gene regulation function of Pax proteins.Paxgenes were previously divided into five groups on the basis of a phylogenetic analysis of paired domains. In this study, two highly similar cnidarianPax-Bgenes fromCladonema californicum,a jellyfish with eyes, were found and sequenced. In an effort to understand the function of the cnidarianPaxgenes isolated in this and a previous study, we characterized the consensus DNA sequences bound by the cnidarian paired domains using a PCR-based method and electrophoretic mobility shift assays. The consensus DNA sequences obtained are very similar to those bound by mammalian Pax proteins. Comparison of known consensus sequences indicates that they are all partially palindromic, but this characteristic is most prominent in cnidarians, which suggests that the DNA sequences bound by the ancestral paired domain could have been palindromic. Also, cnidarian paired domains, like those of Pax-2/5/8, possess a broader binding specificity than other paired domains, which implies that the common ancestor of Pax-2/5/8 and Pax-4/6 paired domains could also have had a similar broad DNA-binding specificity. Thus far, a definitivePax-6gene has not been found in several cnidarian species examined, which is consistent with a later origin of thePax-6gene and raises two possibilities: thePaxgenes of cnidarians are multifunctional and control two or more developmental pathways, including eye development, or they use aPax-independent pathway for eye development. Whether this pathway does exist and is unique to cnidarians or it whether it represents a true master control under whichPax-6was later included remains to be determined.