Scottish Fish Immunology Research Centre, University of Aberdeen, Aberdeen, UK.
Fish Shellfish Immunol. 2013 Jun;34(6):1404-15. doi: 10.1016/j.fsi.2013.02.015. Epub 2013 Feb 28.
CD79α (also known as Igα) is a component of the B cell antigen receptor complex and plays an important role in B cell signalling. The CD79α protein is present on the surface of B cells throughout their life cycle, and is absent on all other healthy cells, making it a highly reliable marker for B cells in mammals. In this study the spiny dogfish (Squalus acanthias) CD79α (SaCD79α) is described and its expression studied under constitutive and stimulated conditions. The spiny dogfish CD79α cDNA contains an open reading frame of 618 bp, encoding a protein of 205 amino acids. Comparison of the SaCD79α gene with that of other species shows that the gross structure (number of exons, exon/intron boundaries, etc.) is highly conserved across phylogeny. Additionally, analysis of the 5' flanking region shows SaCD79α lacks a TATA box and possesses binding sites for multiple transcription factors implicated in its B cell-specific gene transcription in other species. Spiny dogfish CD79α is most highly expressed in immune tissues, such as spleen, epigonal and Leydig organ, and its transcript level significantly correlates with those of spiny dogfish immunoglobulin heavy chains. Additionally, CD79α transcription is up-regulated, to a small but significant degree, in peripheral blood cells following stimulation with pokeweed mitogen. These results strongly indicate that, as in mammals, spiny dogfish CD79α is expressed by shark B cells where it associates with surface-bound immunoglobulin to form a fully functional BCR, and thus may serve as a pan-B cell marker in future shark immunological studies.
CD79α（也称为 Igα）是 B 细胞抗原受体复合物的一个组成部分，在 B 细胞信号转导中发挥重要作用。CD79α 蛋白存在于 B 细胞的整个生命周期中，而在所有其他健康细胞中都不存在，因此是哺乳动物 B 细胞的高度可靠标志物。在这项研究中，描述了尖吻鲛（Squalus acanthias）的 CD79α（SaCD79α），并在组成型和刺激条件下研究了其表达。尖吻鲛 CD79α cDNA 包含一个 618 bp 的开放阅读框，编码一个 205 个氨基酸的蛋白质。将 SaCD79α 基因与其他物种的基因进行比较表明，其总体结构（外显子的数量、外显子/内含子边界等）在整个进化过程中高度保守。此外，对 5'侧翼区的分析表明，SaCD79α 缺乏 TATA 盒，并具有与其他物种中 B 细胞特异性基因转录相关的多个转录因子结合位点。尖吻鲛 CD79α 在免疫组织中表达水平最高，如脾脏、副性腺和莱迪希氏器官，其转录本水平与尖吻鲛免疫球蛋白重链的转录本水平显著相关。此外，外周血细胞在受到 pokeweed mitogen 刺激后，CD79α 的转录水平会小幅度上调。这些结果强烈表明，与哺乳动物一样，尖吻鲛 CD79α 由鲨鱼 B 细胞表达，在 B 细胞中与表面结合的免疫球蛋白结合形成一个完全功能的 BCR，因此在未来的鲨鱼免疫学研究中可能作为 pan-B 细胞标志物。
