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采用RT-PCR和cDNA末端快速扩增技术(rapid amplification of cDNA ends,RACE),首次克隆了西伯利亚鲟(Acipenser baerii)的CXCR7a和CXCR7b基因的全长cDNA。CXCR7a的cDNA全长为2 325 bp(登录号为:JQ034508),包括207 bp的5’端非翻译区(UTR)、可编码362个氨基酸的1 086 bp的开放阅读框(ORF)及包括poly(A)尾巴在内的大小为1 032 bp的3’端非翻译区(UTR);CXCR7b的cDNA全长为2 423 bp(登录号为:JQ034509),包括209 bp的5’端非翻译区(UTR)、可编码370个氨基酸的1 110 bp的开放阅读框(ORF)及包括poly(A)尾巴在内的大小为1 104 bp的3’端非翻译区(UTR),并对它们编码的蛋白质序列的分子特征进行了分析。氨基酸序列相似性(similarity)分析表明,CXCR7a与人(Homo sapiens)、小鼠(Mus musculus)、非洲爪蟾(Xenopus laevis)、斑马鱼(Danio rerio)的CXCR7相似性分别为82.6%、81.4%、80.9%、81.0%;CXCR7b与人、小鼠、非洲爪蟾、斑马鱼的CXCR7相似性分别为82.9%、82.3%、80.8%、82.5%;西伯利亚鲟CXCR7a与其CXCR7b的相似性最高为96.5%。系统进化树分析显示,西伯利亚鲟与斑马鱼聚为一簇,两栖类聚为一簇,其它高等脊椎动物再进行聚类。对CXCR7a和CXCR7b在各发育时期胚胎及仔鱼的表达状况分别进行定性分析表明,CXCR7a在除卵裂期、囊胚期的胚胎外,其在原肠胚中期至出膜1 d的仔鱼的各时期中均具有表达,CXCR7b在卵裂期至出膜1 d的仔鱼的各时期中均具有表达。另外,从基因组DNA水平上表明CXCR7a和CXCR7b来自不同的基因拷贝。这些结果为进一步研究CXCR7在西伯利亚鲟侧线系统发育中的作用提供了新的基础资料。
The full-length cDNA of CXCR7a and CXCR7b genes of Acipenser baerii was cloned for the first time by RT-PCR and rapid amplification of cDNA ends (RACE). The full-length cDNA of CXCR7a is 2 325 bp (accession number: JQ034508), including a 207 bp 5 ’untranslated region (UTR), an open reading frame (ORF) of 1 866 bp that encodes 362 amino acids, (A) tail of 1 032 bp 3 ’untranslated region (UTR). The full-length cDNA of CXCR7b is 2 423 bp (accession number: JQ034509), including 209 bp 5’ untranslated region (UTR), a 1 110 bp open reading frame (ORF) encoding 370 amino acids and a 3 104 untranslated region (UTR) of 1 104 bp including the poly (A) tail, and encoding them The molecular characteristics of the protein sequence were analyzed. Amino acid sequence similarity analysis showed that the CXCR7 similarity between CXCR7a and Homo sapiens, Mus musculus, Xenopus laevis and Danio rerio were 82.6% and 81.4% respectively, , 80.9%, 81.0%. The CXCR7 similarity between CXCR7b and human, mouse, Xenopus laevis and zebrafish was 82.9%, 82.3%, 80.8% and 82.5% respectively. The highest similarity between CXCR7a and CXCR7b was 96.5% . Phylogenetic tree analysis showed that Siberian sturgeon clustered with zebrafish, amphibians clustered together, and other higher vertebrates clustered again. The qualitative analysis of the expression status of CXCR7a and CXCR7b in embryos and larvae at different developmental stages showed that CXCR7a was expressed in embryos except cleavage stage and blastocyst stage, Both CXCR7b and CXCR7b expressed in different stages of larvae, ranging from cleavage stage to 1 day. In addition, it was shown from genomic DNA that CXCR7a and CXCR7b were derived from different gene copies. These results provide new basic data for further study on the role of CXCR7 in the lateral development of Siberian sturgeon.