Spec2 genes of Strongylocentrotus purpuratus. Structure and differential expression in embryonic aboral ectoderm cells.
Spec2 genes of Strongylocentrotus purpuratus. Structure and differential expression in embryonic aboral ectoderm cells.
复制标题
Strongylocentrotus purpuratus 的 Spec2 基因。
DOI：
10.1016/0022-2836(88)90275-6
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发表时间：
1988
影响因子：
5.6
通讯作者：
Klein,WH
中科院分区：
文献类型：
--
作者：
Hardin,PE;Angerer,LM;Hardin,SH;Angerer,RC;Klein,WH
Spec基因家族的成员在海胆（Strongylocentrotus purpuratus）的胚胎发育过程中表达。该家族编码与钙调蛋白/肌钙蛋白C/肌球蛋白轻链组钙结合蛋白相关的蛋白质，其中一个基因Specl已在我们实验室进行了广泛研究。在本文中，我们分析了该家族的其他成员，统称为Spec 2基因。我们利用几个杂交探针来自Spec 1和Spec 2的cDNA克隆，识别不同的家庭成员。基因组DNA凝胶印迹和狭缝印迹分析表明，S.紫色基因组描述了Spec 2基因Spec 2a、Spec 2c和Spec 2d的结构。基因组的60 kb（kb = 103个碱基或碱基对）区域包含连锁的Spec 1-Spec 2c基因，两个独立的20 kb区域包含Spec 2a和Spec 2d基因。重复序列家族的六个成员分散在基因的不同位置。绘制了3个Spec 2基因的转录起始位点，并对5′-侧翼DNA的400 - 500个碱基对进行了测序。所有三个Spec 2基因都在第一个外显子3′端上游约120个碱基对处启动转录。相比之下，Spec 1转录物的5′端开始于上游约107个碱基对，因此它含有5′非翻译序列，对应于Spec 2基因的非转录5′侧翼序列。除了TATA共有序列和重复的三核苷酸AAC之外，Spec 2基因的CAP位点上游序列之间几乎没有相似性。Spec 2a/Spec 2c mRNA开始积累数小时后，在晚期囊胚-早期原肠胚阶段，达到Spec 1水平的约40 - 60%; Spec 2d主要在原肠胚和胚胎期积累，其水平仅为2%，与识别所有Spec 2 mRNA或仅识别Spec 2d mRNA的探针原位杂交显示，与Spec 1一样，这些mRNA仅限于无口外胚层细胞及其前体。Spec基因家族代表了一组相关基因，其mRNA在胚胎发生过程中在相同的细胞类型中积累，但在不同的时间和不同的水平。
Members of the Spec gene family are expressed during embryonic development of the sea urchin,Strongylocentrotus purpuratus. The family encodes proteins related to the calmodulin/troponin C/myosin light chain group of calcium binding proteins and one gene, Specl, has been studied extensively in our laboratory. In this paper, we analyze other members of the family, collectively termed Spec2 genes. We make use of several hybridization probes derived from Spec1 and Spec2 cDNA clones, which recognize different members of the family. Genomic DNA gel blot and slot blot analyses show that there are approximately eight Spec genes in theS. purpuratusgenome. The structures of three Spec2 genes, Spec2a, Spec2c and Spec2d, are described. A 60 kb (kb = 103bases or base-pairs) region of the genome contains the linked Spec1-Spec2c genes and two separate 20 kb regions contain the Spec2a and Spec2d genes. Six members of a repetitive sequence family are dispersed at various locations among the genes. The transcriptional initiation sites of the three Spec2 genes are mapped, and 400 to 500 base-pairs of 5′-flanking DNA sequenced. All three Spec2 genes initiate transcription approximately 120 base-pairs upstream from the 3′ end of the first exon. In contrast, the 5′ end of the Specl transcript begins about 107 base-pairs farther upstream, so it contains 5′ untranslated sequences that correspond to non-transcribed 5′-flanking sequences of the Spec2 genes. There is little similarity among the sequences upstream from the CAP site of the Spec2 genes except the TATA consensus sequence and a repeating trinucleotide, AAC. Measurements of Spec mRNA levels during embryogenesis show that Specl mRNA begins to accumulate at the early blastula stage and is the most abundant; Spec2a/Spec2c mRNAs begin accumulating several hours later at the late blastula-early gastrula stage and reach about 40 to 60% the levels of Spec1; and Spec2d mRNAs accumulate mostly during the gastrula and pluteus stages with levels reaching only 2% those of Spec1.In situhybridization with probes that recognize either all Spec2 mRNAs or only Spec2d mRNAs show that, like Spec1, these mRNAs are restricted to aboral ectoderm cells and their precursors. The Spec gene family represents a group of related genes whose mRNAs all accumulate in the same cell type but at different times and to different levels during embryogenesis.