Weisberg L J, Shiu D T, Conkling P R, Shuman M A
Blood. 1987 Aug;70(2):579-82.
Factor XIII is the fibrin-stabilizing factor that covalently cross-links fibrin monomers to form a highly organized, stable fibrin clot. The plasma form of factor XIII is a heterodimer, a2b2, consisting of two a-chains and two b-chains; the intracellular form, such as in platelets and placenta, is a dimer, a2, consisting of a-chains only. The catalytic function of factor XIII, a transglutaminase, resides in the a-chain. To address questions regarding sites of synthesis of factor XIII a-chain, an EcoRI restriction fragment from the protein-coding region of the factor XIII a-chain cDNA was used as a probe for Northern blot analysis. The cDNA probe showed hybridization with a single approximately 4.0-kilobase (kb) message in poly (A)+ mRNA prepared from normal human peripheral blood monocytes and normal human liver. The results demonstrate conclusively that factor XIII a-chains are actively synthesized in circulating monocytes and in liver. To our knowledge, these data represent the first demonstration of synthesis of any blood coagulation factor in primary uncultured and unstimulated monocytes or macrophage cells.
因子 XIII 是纤维蛋白稳定因子，它通过共价交联纤维蛋白单体形成高度有序、稳定的纤维蛋白凝块。因子 XIII 的血浆形式是一种异源二聚体，即 a2b2，由两条 a 链和两条 b 链组成；细胞内形式，如在血小板和胎盘中，是一种二聚体，即 a2，仅由 a 链组成。因子 XIII 的催化功能（一种转谷氨酰胺酶）存在于 a 链中。为了解决有关因子 XIII a 链合成位点的问题，来自因子 XIII a 链 cDNA 蛋白质编码区的一个 EcoRI 限制片段被用作 Northern 印迹分析的探针。该 cDNA 探针在从正常人外周血单核细胞和正常人肝脏制备的聚腺苷酸（poly(A)+）mRNA 中与一条约 4.0 千碱基（kb）的单一信使核糖核酸（mRNA）显示出杂交信号。结果确凿地证明，因子 XIII a 链在循环单核细胞和肝脏中被积极合成。据我们所知，这些数据首次证明了在未培养和未刺激的原代单核细胞或巨噬细胞中合成任何血液凝固因子。
