DNA-SEQUENCES MEDIATING CLASS SWITCHING IN ALPHA-IMMUNOGLOBULINS
DNA-SEQUENCES MEDIATING CLASS SWITCHING IN ALPHA-IMMUNOGLOBULINS
复制标题
DOI：
10.1126/science.6774415
复制
发表时间：
1980-01-01
期刊：
影响因子：
56.9
通讯作者：
HOOD, LE
中科院分区：
文献类型：
--
作者：
DAVIS, MM;KIM, SK;HOOD, LE
免疫球蛋白类别转换涉及在B淋巴细胞分化期间编码重链恒定区（CH）的基因片段的特异性DNA重排。在本文研究的两种不同的Cμ到Cα转换的情况（T15和M603）和一种取自文献的情况（MC 101）中，在CH转换过程中，Cμ 5′侧的三个不同位点和Cα 5′侧的三个不同位点连接在一起。三个生殖系Cα重组位点周围的序列是高度保守的30个核苷酸的区段，可能作为CH转换到Cα基因的识别序列。该推定识别序列在种系Cα5′侧翼序列的约1400个核苷酸中重复17次。该Cα序列与报告的Cγ 1和Cγ 2b开关位点序列之间缺乏同源性，表明重链开关是由类别特异性识别序列介导的，并且可能是由类别特异性调控机制介导的。此外，在一个例子（MC101）中，CH转换从Cμ到Cα再到Cγ1。这种转换途径可能会给CH转换的简单缺失模型带来困难。
Immunoglobulin class switching involves specific DNA rearrangements of the gene segments coding for heavy chain constant regions (CH) during B lymphocyte differentiation. In two different cases of Cμto Cαswitching examined here (T15 and M603) and one taken from the literature (MC101), three different sites on the 5′ side of Cμand three different sites on the 5′ side of Cαare joined together in the process of CHswitching. The sequences surrounding the three germ-line Cαsites of recombination are highly conserved blocks of 30 nucleotides that may serve as recognition sequences for CHswitching to the Cαgene. This putative recognition sequence is repeated 17 times in approximately 1400 nucleotides of the germ-line Cα5′ flanking sequence. The lack of homology between this Cαsequence and sequences reported for the Cγ1and Cγ2bswitch sites suggests that heavy chain switching is mediated by class-specific recognition sequences and, presumably, class-specific regulatory mechanisms. In addition, it appears that in one example (MC101) CHswitching progressed from Cμto Cαto Cγ1. This switching pathway may present difficulties for the simple deletional model of CHswitching.