Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive MC 0212, La Jolla, CA 92037, United States.
Dev Comp Immunol. 2010 Aug;34(8):785-90. doi: 10.1016/j.dci.2010.02.014. Epub 2010 Mar 16.
The gene sequence encoding an N-terminal collagen stalk followed by a globular complement 1q domain (gC1q), an architecture that characterizes the C1q A, B and C chains of the first complement component (C1), did not become prevalent until the cephalochordates and urochordates. However, genes encoding only the globular complement 1q domain (ghC1q) are more ancient as they exist within many lower vertebrate and invertebrate genomes, and are even present in the prokaryotes. These genes can be divided into two groups, the first, which appears to be the more ancient form, encodes proteins that are not secreted (cghC1q). The second group encodes proteins in which the globular domain is preceded by a signal peptide indicating secretion (sghC1q). In this review we examine bioinformatic evidence for C1q domain containing (C1qDC) genes in many organisms and integrate these observations with research performed and published on the biochemistry and functions of this fascinating set of proteins.
该基因序列编码一个 N 端胶原蛋白柄，其后是一个球形补体 1q 结构域（gC1q），这种结构特征是第一个补体成分（C1）的 C1qA、B 和 C 链的特征。直到头索动物和尾索动物，这种基因才变得普遍存在。然而，只编码球形补体 1q 结构域（ghC1q）的基因更为古老，因为它们存在于许多低等脊椎动物和无脊椎动物的基因组中，甚至存在于原核生物中。这些基因可以分为两组，第一组似乎是更古老的形式，编码不分泌的蛋白质（cghC1q）。第二组编码的蛋白质中，球形结构域前有一个信号肽表明分泌（sghC1q）。在这篇综述中，我们检查了许多生物体中含有 C1q 结构域的（C1qDC）基因的生物信息学证据，并将这些观察结果与对这组迷人蛋白质的生物化学和功能进行的研究和发表的研究结合起来。
