Molecular analysis of chicken embryo SPARC (osteonectin).
Molecular analysis of chicken embryo SPARC (osteonectin).
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鸡胚 SPARC（骨连接素）的分子分析。
DOI：
10.1111/j.1432-1033.1993.tb18358.x
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Sage,EH
中科院分区：
文献类型：
--
作者：
Bassuk,JA;Iruela-Arispe,ML;Lane,TF;Benson,JM;Berg,RA;Sage,EH
SPARC 是一种分泌性糖蛋白，可调节细胞形状和细胞-基质相互作用。 SPARC 水平在胚胎体节发生、成骨和血管生成部位以及成人伤口修复过程中增加。我们从鸡胚中克隆并鉴定了 SPARC。通过聚合酶链反应的新用途获得的 2.2 kbp cDNA 被确定编码与人类 SPARC 85% 相同的 298 个残基蛋白质。尤其是抗原位点似乎高度保守，因为针对鼠和牛 SPARC C 末端序列的抗体与鸡胚提取物中的 41-43 kDa 蛋白质发生反应。鸡 SPARC 可以通过四个序列特征来定义：(a) 结构域 II 中 11 个半胱氨酸残基的保守间隔，(b) 结构域 II 中的五肽 KKGHK，其包含在由 31 个相同残基组成的更大区域内，(c) 结构域 III 中 10 个残基的 100% 保守区域，以及 (d) C 末端钙结合 EF 手基序。 10 日龄鸡胚中的 SPARC mRNA 有 1.8、2.2 和 3.0 kb 三种大小。 2.2-kb mRNA 的相对稳态水平确定为主动脉 ≥ 骨骼肌 > 颅骨 > 椎骨 > 前肢 > 肾脏 > 心脏 > 大脑 > 皮肤和肺 ≥ 肝脏。 1.8-kb 和 2.2-kb mRNA 的相对丰度在不同组织中存在差异，表明 SPARC mRNA 的加工可能存在差异。所有三种 RNA 种类均通过编码区 N 末端部分的 cDNA 探针检测到。因此，这三种 mRNA 似乎源自差异的 3' 剪接和/或多聚腺苷酸化。集体证据表明 SPARC 在脊椎动物进化过程中得到了很好的保守，这一发现表明了这种蛋白质在发育中的基本作用。
SPARC is a secreted glycoprotein that modulates cell shape and cell‐matrix interactions. Levels of SPARC are increased at sites of somitogenesis, osteogenesis, and angiogenesis in the embryo and during wound repair in the adult. We have cloned and characterized SPARC from chicken embryo. A 2.2‐kbp cDNA, obtained by a novel use of the polymerase chain reaction, was determined to encode a 298‐residue protein that is 85% identical to human SPARC. Antigenic sites in particular appear to be highly conserved, as antibodies against C‐terminal sequences of murine and bovine SPARC reacted with a 41–43 kDa protein in chicken embryo extracts. Chicken SPARC can be defined by four sequence signatures: (a) a conserved spacing of 11 cysteine residues in domain II, (b) the pentapeptide KKGHK in domain II, which is contained within a larger region of 31 identical residues, (c) a 100% conserved region of 10 residues in domain III, and (d) a C‐terminal, calcium‐binding EF‐hand motif. SPARC mRNAs in the 10‐day‐old chicken embryo are represented by three sizes of 1.8, 2.2 and 3.0 kb. The relative steady‐state levels for the 2.2‐kb mRNA were determined as aorta ≥ skeletal muscle > calvarium > vertebra > anterior limb > kidney > heart > brain > skin and lung ≥ liver. The relative abundance of the 1.8‐kb and 2.2‐kb mRNAs varied among tissues and indicated that differential processing of SPARC mRNAs might occur. All three RNA species were detected by a cDNA probe for the N‐terminal part of the coding region. Thus, the three mRNA species appear to arise from differential 3′ splicing and/or polyadenylation. Collective evidence demonstrates that SPARC has been well‐conserved during vertebrate evolution, a finding that indicates a fundamental role for this protein in development.