CHARACTERIZATION OF THE MOUSE TYPE-X COLLAGEN GENE
CHARACTERIZATION OF THE MOUSE TYPE-X COLLAGEN GENE
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DOI：
10.1016/s0934-8832(11)80075-2
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发表时间：
1993-03-01
期刊：
影响因子：
--
通讯作者：
OLSEN, BR
中科院分区：
文献类型：
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作者：
APTE, SS;OLSEN, BR
X 型胶原蛋白是 alpha1(X) 多肽链的同源三聚体，由正在经历软骨内骨化的软骨区域的肥大软骨细胞特异性表达。我们之前已经表征了含有小鼠 X 型胶原基因 (col10a1) 的主要部分的基因组克隆，并将 col10a1 的基因座分配给小鼠 10 号染色体 (Apte 等人，Eur. J. Biochem. 224: 217-224, 1992)。在本文中，通过 cDNA 和基因组克隆的额外表征，我们描述了 col10a1 基因的完整组织。 col10a1 基因大小为 7.2 kb，与小鸡一样，col10a1 基因转录本仅由三个外显子生成。外显子 1 仅编码 mRNA 的 5' 非翻译 (5' UT) 区域，并通过长度为 562 bp 的内含子与外显子 2 分开。外显子 2 (169 bp) 编码 15 bp 的 5' UT 信息、翻译起始点以及假定信号肽的 17 个氨基酸残基，以及假定的 X 型胶原 N 端非胶原 (NC2) 结构域的 33 1/2 密码子。外显子 3 大小为 2854 bp，编码 NC2 结构域的 4 2/3 个密码子、463 个残基 (COL) 的整个胶原结构域、整个 C 端非胶原 (NC1) 结构域（161 个氨基酸残基）和 mRNA 的整个 965 bp 3' 非翻译 (3' UT) 序列。 col10a1 启动子中串联存在两个 TATA 盒。两个 TATA 盒在转录中都很活跃，产生两个具有不同 5' 末端的转录物群体；较长的转录物丰度较低，只能在新生小鼠中通过 PCR 检测到。 col10a1 启动子包含 CCAAT 盒以及结合潜在转录因子所需的其他共有序列元件。 col10a1 基因的表征为研究哺乳动物软骨内骨生长和发育过程中 X 型胶原蛋白表达的调节提供了必要的数据。了解小鼠 X 型胶原基因的完整结构也将有助于研究小鼠软骨发育不良中的 X 型胶原基因异常以及转基因小鼠的产生。
Type X collagen, a homotrimer of alpha1(X) polypeptide chains, is specifically expressed by hypertrophic chondrocytes in regions of cartilage undergoing endochondral ossification. We have previously characterized a genomic clone containing the major part of the mouse type X collagen gene (col10a1) and assigned the locus for col10a1 to mouse chromosome 10 (Apte et al., Eur. J. Biochem. 224: 217-224, 1992). In this paper, through additional characterization of cDNA and genomic clones, we describe the complete organization of the col10a1 gene. The col10a1 gene is 7.2 kb in size and, as in the chick, col10a1 gene transcripts are generated from only three exons. Exon 1 encodes only the 5' untranslated (5' UT) region of the mRNA and is separated from exon 2 by an intron 562 bp in length. Exon 2 (169 bp) encodes 15 bp of 5' UT message, the translation start plus 17-amino acid residues of the putative signal peptide, and 33 1/2 codons of the putative N-terminal non-collagenous (NC2) domain of type X collagen. Exon 3 is 2854 bp in size and encodes 4 2/3 codons of the NC2 domain, the entire collagenous domain of 463 residues (COL), the entire C-terminal non-collagenous (NC1) domain (161 amino acid residues) and the entire 965 bp 3' untranslated (3' UT) sequence of the mRNA. Two TATA boxes are present in tandem in the col10a1 promotor. Both TATA boxes are active in transcription, generating two populations of transcripts with different 5'-termini; the longer transcript is of low abundance and is detectable only by PCR in newborn mice. The col10a1 promotor contains a CCAAT box as well as other consensus sequence elements required for binding of potential transcription factors. Characterization of the col10a1 gene provides data essential for studies of the regulation of type X collagen expression during mammalian endochondral bone growth and development. Knowledge of the complete structure of the mouse type X collagen gene will also be useful for the investigation of type X collagen gene abnormalities in murine chondrodysplasias and for the generation of transgenic mice.