cDNA cloning and chromosomal mapping of the mouse type VII collagen gene (Col7a1): evidence for rapid evolutionary divergence of the gene.
cDNA cloning and chromosomal mapping of the mouse type VII collagen gene (Col7a1): evidence for rapid evolutionary divergence of the gene.
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小鼠 VII 型胶原蛋白基因 (Col7a1) 的 cDNA 克隆和染色体作图：该基因快速进化分化的证据。
DOI：
10.1006/geno.1993.1255
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发表时间：
1993
期刊：
影响因子：
4.4
通讯作者：
Uitto,J
中科院分区：
文献类型：
--
作者：
Li,K;Christiano,AM;Copeland,NG;Gilbert,DJ;Chu,ML;Jenkins,NA;Uitto,J
VII型胶原是锚定原纤维的主要成分，锚定原纤维是真皮-表皮基底膜区的关键附着结构。与最近克隆的人VII型胶原cDNA的遗传连锁分析表明，相应的基因，COL 7A 1，是在营养不良型大疱性表皮病的候选基因。为了深入了解COL 7A 1的进化保守性，在这项研究中，我们已经分离出小鼠VII型胶原蛋白的cDNA筛选小鼠表皮角质形成细胞的cDNA文库与人类COL 7A 1的cDNA。分离出两个重叠的小鼠cDNA，小鼠表皮角质形成细胞RNA与其中之一的北方杂交显示存在约9.5 kb的mRNA转录物，其大小与人COL 7A 1 mRNA的大小近似。小鼠cDNA的核苷酸测序显示了一个2760 bp的开放阅读框架，编码胶原结构域的5′端一半和NC-1的一个片段，NC-1是VII型胶原的非胶原氨基末端结构域。小鼠的氨基酸序列与相应的人从cDNA推导的序列的比较显示82.5%的同一性。与其他胶原基因相比，该基因的进化分化相对较快。尽管序列变异程度很高，但几个序列，包括Gly-X-Y重复序列中非胶原缺陷和中断的大小和位置，都是精确保守的。最后，通过种间回交定位小鼠Col 7A 1基因到小鼠9号染色体，该区域对应于人染色体3 p21，人Col 7A 1的位置。这一分配确认并扩展了小鼠和人类染色体在基因组这一区域的关系。
Type VII collagen is the major component of anchoring fibrils, critical attachment structures at the dermal-epidermal basement membrane zone. Genetic linkage analyses with recently cloned human type VII collagen cDNAs have indicated that the corresponding gene, COL7A1, is the candidate gene in the dystrophic forms of epidermolysis bullosa. To gain insight into the evolutionary conservation of COL7A1, in this study we have isolated mouse type VII collagen cDNAs by screening a mouse epidermal keratinocyte cDNA library with a human COL7A1 cDNA. Two overlapping mouse cDNAs were isolated, and Northern hybridization of mouse epidermal keratinocyte RNA with one of them revealed the presence of a mRNA transcript of ∼9.5 kb, the approximate size of the human COL7A1 mRNA. Nucleotide sequencing of the mouse cDNAs revealed a 2760-bp open reading frame that encodes the 5′ half of the collagenous domain and a segment of the NC-1, the noncollagenous amino-terminal domain of type VII collagen. Comparison of the mouse amino acid sequences with the corresponding human sequences deduced from cDNAs revealed 82.5% identity. The evolutionary divergence of the gene was relatively rapid in comparison to other collagen genes. Despite the high degree of sequence variation, several sequences, including the size and the position of noncollagenous imperfections and interruptions within the Gly-X-Y repeat sequence, were precisely conserved. Finally, the mouseCol7a1gene was located by interspecific backcross mapping to mouse Chromosome 9, a region that corresponds to human chromosome 3p21, the position of human COL7A1. This assignment confirms and extends the relationship between the mouse and the human chromosomes in this region of the genome.