Isolation and characterization of cDNA clones encoding the human carcinoembryonic antigen reveal a highly conserved repeating structure.
Isolation and characterization of cDNA clones encoding the human carcinoembryonic antigen reveal a highly conserved repeating structure.
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编码人癌胚抗原的 cDNA 克隆的分离和表征揭示了高度保守的重复结构。
DOI：
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发表时间：
1987
影响因子：
11.1
通讯作者：
S. Kleist
中科院分区：
文献类型：
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作者：
W. Zimmermann;B. Ortlieb;R. Friedrich;S. Kleist
为了分离编码癌胚抗原（CEA）的cDNA克隆，我们构建了人结肠肿瘤mRNA的cDNA文库。用各种寡核苷酸筛选文库，所述寡核苷酸的序列已经从CEA的部分氨基酸序列数据推导。阳性候选克隆与重复DNA探针杂交，因为CEA mRNA含有Alu重复元件，并与非特异性交叉反应抗原（与CEA密切相关的抗原）的基因组克隆片段杂交。在这里，我们报告的核苷酸序列的两个重叠的CEA cDNA克隆，包括1422个核苷酸的CEA mRNA。该序列编码CEA的372个COOH末端氨基酸，随后是含有截短的Alu重复的305个核苷酸的3'非翻译序列。预测的蛋白质序列由两个包含178个氨基酸的重复序列组成，每个重复序列的同源性极高，为67%。每个重复单元含有四个保守的半胱氨酸残基和六至九个推定的N-糖基化位点。CEA mRNA在原发性结肠肿瘤中表达最强，在正常结肠组织中表达程度较低。在HeLa细胞和正常人成纤维细胞中未发现CEA mRNA。
For the isolation of cDNA clones encoding the carcinoembryonic antigen (CEA), we have constructed a cDNA library from human colon tumor mRNA. The library was screened with various oligonucleotides whose sequence had been deduced from partial amino acid sequence data for CEA. Positive candidate clones were hybridized with a probe for repetitive DNA, because CEA mRNA contains an Alu repetitive element, and with a fragment of a genomic clone of nonspecific cross-reacting antigen, an antigen closely related to CEA. Here we report the nucleotide sequence of the two overlapping CEA cDNA clones comprising 1422 nucleotides of CEA mRNA. This sequence encodes the 372 COOH-terminal amino acids of CEA followed by 305 nucleotides of 3' untranslated sequence containing a truncated Alu repeat. The predicted protein sequence is composed of two repeats comprising 178 amino acids, each with an exceptionally high homology of 67%. Each repeat unit contains four conserved cysteine residues and six to nine putative N-glycosylation sites. CEA mRNA is most strongly expressed in primary colon tumors and, to a lesser extent, in normal colonic tissue. No CEA mRNA is found in HeLa cells and normal human fibroblasts.