STRUCTURAL ANALYSIS OF ETS-RELATED GENES IN LOWER EUKARYOTES

低等真核生物中ETS家族基因的研究主要集中在：1)可能 面包酵母(Saccharmyces Cerevisiae)的Ets序列；2)erg 在海胆中发现的同源物；3)在禽白血病病毒E26中发现的倒位 4)整个ETS家族的系统发育分析。(1)低 四种不同酶消化的酿酒酵母DNA的严格杂交 放射性标记的海胆ETS探针发现了几组酶 每组酶大约有四条主要条带。三个独特的 分离到与ETS序列杂交的噬菌体lambda克隆 在相同条件下对酿酒酵母基因组文库进行筛选。 (2)发现了海胆Lytechinus varegatus的基因组克隆 是ETS家族基因ERG和Fli-1的同源基因。它包含一个 开放阅读框，其中173个氨基酸编码区起始于 拼接受体位置。这些氨基酸中的前84个与 所有ETS家族基因，而序列的其余部分代表一个 高度保守的ERG特异域。(3)E26基因组片段 在p135gag-myb-ETS的末端附近发现了开放阅读框 以包含鸡Ets-1序列的倒置。倒置 含有至少41个碱基对，可能长达46个碱基对。这将导致 用16个氨基酸取代鸡Ets-1的13个氨基酸 来源于正常Ets-1编码链的反向互补或 通读到E26环境序列。改变后的羧基末端 序列可能是导致不同致癌潜能的v- ETS，与鸡ETS-1形成对比。(4)32个亚种的系统发育分析 Ets序列分析表明，该基因家族可分为11个 子组。通过对这些星系团的分析，可以了解它们的演化历史 将在后生动物的背景下检查ETS基因家族的 辐射。在三个门中发现了与ETS相关的同源基因 (脊索动物、棘皮动物和节肢动物)。在10个小组中，有4个小组 代表在一个以上的门，暗示有几个基因 复制发生在这些门的分歧超过500之前 百万年前。

Studies of ets family genes in lower eukaryotes focused on: 1) possible ets sequences in the baker's yeast (Saccharomyces cerevisiae); 2) an erg homolog in a sea urchin; 3) an inversion found in avian leukemia virus E26 v-ets; 4) a phylogenetic analysis of the entire ets family. (1) Low stringency hybridization of S. cerevisiae DNA digested by four different sets of enzymes to a radiolabeled sea urchin ets probe revealed approximately four major bands for each set of enzymes. Three unique bacteriophage lambda clones that hybridize to ets sequences were isolated by screening a S. cerevisiae genomic library under the same conditions. (2) A genomic clone from the sea urchin Lytechinus variegatus was found to be the homolog of the ets family genes, ERG and Fli-1. It contains an open reading frame, of which the 173 amino acid coding region begins at a splice acceptor site. The first 84 of these amino acids are homologous to all ets family genes, while the remainder of the sequence represents a highly-conserved erg-specific domain. (3) The segment of the E26 genome near the termination of the p135gag-myb-ets open reading frame was found to contain an inversion of the chicken ets-1 sequence. The inversion contains at least 41 bp, and may be as large as 46 bp. This results in the replacement of 13 amino acids of chicken ets-1, with 16 amino acids derived from the reverse complement of the normal ets-1 coding strand or read-through into E26 env sequences. The altered carboxy terminal sequences may be responsible for the different oncogenic potential of v- ets, as contrasted to chicken ets-1. (4) A phylogenetic analysis of 32 ets sequences revealed that this family of genes may be divided into 11 subgroups. Analysis of these clusters allows the history of the evolution of the ets gene family to be examined in the context of metazoan radiation. Homologous ets-related genes have been found in three phyla (Chordata, Echinodermata, and Arthropoda). Of the 10 subgroups, 4 have representatives in more than one phyla, implying that several gene duplications occurred prior to the divergence of these phyla over 500 million years ago.