The Products of Pre-B Cell-specific Genes ( X 5 and Vp , . B ) and the Immunoglobulin iu Chain Form a Complex That Is Transported onto the Cell Surface
The Products of Pre-B Cell-specific Genes ( X 5 and Vp , . B ) and the Immunoglobulin iu Chain Form a Complex That Is Transported onto the Cell Surface
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Pre-B 细胞特异性基因（X 5 和 Vp , . B ）和免疫球蛋白 iu 链的产物形成复合物，并被转运到细胞表面
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
M. Reth
中科院分区：
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作者：
T. Tsubata;M. Reth
B 细胞表面，而游离 H 链则保留在与 BiP 相关的内质网 (ER) 中 (1)。然而，在仅产生 lc H 链的前 B 系中，少量 P 链在细胞表面表达，表明一些其他蛋白质替代了这些细胞中缺失的 L 链。事实上，14-22 kD 的蛋白质已被证明可以与鼠类和人类 pre-B 系中的细胞质和表面 p, 链结合 (2-4)。 X5 和 VpreB 基因在 pre-13 细胞中特异性表达，分别与 XL 链基因的 C 和 V 区具有很强的同源性 (5, 6)，因此很可能编码 p 结合蛋白。对人 X5 和 VpreB 肽具有特异性的抗体分别与人 pre-13 系中 22 和 18 kD 的 A 结合分子发生反应 (7, 8)。然而，这些蛋白质是否与细胞表面的A链相关表达尚未得到证实。我们将编码鼠 A5 和 VpreB 基因的表达载体与 it 载体 (pSVAtm) 一起引入 Ig 骨髓瘤细胞，并证明这两个基因的产物对于细胞表面的 p 表达是必需的且足够的。该结果表明X5和VpreB是前B细胞中sIg的必需成分。
the surface of B cells, while free H chains are retained in the endoplasmic reticulum (ER) in association with BiP (1) . However, in pre-B lines that produce only lc H chains, small amounts of P. chains are expressed on the cell surface, suggesting that some other proteins substitute for the missing L chain in these cells. In fact, proteins of 14-22 kD have been shown to bind to the cytoplasmic and surface p, chains in murine and human pre-B lines (2-4) . The X5 and VpreB genes, which are specifically expressed in pre-13 cells, have strong homology to the C and the V regions of the X L chain genes, respectively (5, 6), and thus, are likely to encode the p-binding proteins. Antibodies specific for the human X5 and VpreB peptides react against A-binding molecules of 22 and 18 kD, respectively, in human pre-13 lines (7, 8) . However, whether these proteins are expressed in association with the A chain on the cell surface has not yet been shown. We introduced expression vectors coding for the murine A5 and VpreB genes, together with a it vector (pSVAtm), into Ig myeloma cells and we demonstrate that the products of the two genes are required and sufficient for p, expression on the cell surface. This result suggests that X5 and VpreB are essential components of sIg in pre-B cells .