HYPERMUTATION IS OBSERVED ONLY IN ANTIBODY-H CHAIN-V REGION TRANSGENES THAT HAVE RECOMBINED WITH ENDOGENOUS IMMUNOGLOBULIN H DNA - IMPLICATIONS FOR THE LOCATION OF CIS-ACTING ELEMENTS REQUIRED FOR SOMATIC MUTATION
HYPERMUTATION IS OBSERVED ONLY IN ANTIBODY-H CHAIN-V REGION TRANSGENES THAT HAVE RECOMBINED WITH ENDOGENOUS IMMUNOGLOBULIN H DNA - IMPLICATIONS FOR THE LOCATION OF CIS-ACTING ELEMENTS REQUIRED FOR SOMATIC MUTATION
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DOI：
10.1084/jem.177.3.797
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发表时间：
1993-03-01
影响因子：
15.3
通讯作者：
MANSER, T
中科院分区：
文献类型：
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作者：
GIUSTI, AM;MANSER, T
使用具有含有抗体H链V区（V（H）DJ（H））基因的转基因的小鼠分析免疫球蛋白（IG）V基因超突变所需的顺式作用元件。这些转基因可以与内源性IgH DNA体细胞重组，导致形成部分由转基因V（H）DJ（H）编码的功能性重（H）链。所分析的五种不同小鼠品系中的转基因组含有少至150 bp，多至2.8 kb的位于V（H）5'侧侧翼的天然DNA和位于V（H）3'侧侧翼的1.5或2.3 kb（包括内含子增强子和5'基质附着区[MAR]）。从免疫的转基因小鼠构建杂交瘤，并对这些杂交瘤中存在的已经或尚未重组以形成功能性H链基因座的转基因进行测序。获得的数据表明：（a）重组的转基因含有高度突变的V（H）基因;和（B）在这些转基因中，甚至那些只含有150 bp的天然V（H）5 ′侧翼序列和5 ′质粒载体序列的几个内切酶的转基因也显示出常规IgH基因座特征性突变的频率、分布和类型。数据还表明，未与内源性IgH DNA重组的转基因V（H）DJ（H）基因不是超突变的底物，即使它们的侧翼是2.8 kb的天然5' DNA和2.3 kb的天然3' DNA，包括J（H）2-J（H）4区、MAR和内含子增强子。总的来说，数据表明，V（H）启动子的5'序列是重复的，V（H）启动子和内含子IgH增强子区是不够的，IgH恒定区基因座内或3'的区域对于IG V（H）转基因的超突变是必需的。
Mice with transgenes containing an antibody H chain V region (V(H)DJ(H)) gene were used in an analysis of the cis-acting elements required for hypermutation of immunoglobulin (Ig) V genes. These transgenes can somatically recombine with endogenous IgH DNA, leading to the formation of functional heavy (H) chains partially encoded by the transgenic V(H)DJ(H). The transgenomes in the five different lines of mice analyzed contain as little as 150 bp, and as much as 2.8 kb of natural DNA flanking the 5' side of the V(H) and either 1.5 or 2.3 kb (including the intronic enhancer and 5' matrix attachment region [MAR]) flanking the 3' side of V(H). Hybridomas were constructed from immunized transgenic mice, and transgenes present in these hybridomas that had or had not recombined to form functional H chain loci were sequenced. The data obtained show that: (a) the recombined transgenes contain hypermutated V(H) genes; and (b) among such transgenes, even those containing only 150 bp of natural V(H) 5' flanking sequence and several kilobases of 5' plasmid vector sequence display a frequency, distribution, and type of mutation characteristic of conventional IgH loci. The data also indicate that transgenic V(H)DJ(H) genes that have not recombined with endogenous IgH DNA are not substrates for hypermutation, even if they are flanked by 2.8 kb of natural 5' DNA, and 2.3 kb of natural 3' DNA, including the J(H)2-J(H)4 region, a MAR, and the intronic enhancer. Collectively, the data suggest that sequences 5' of the V(H) promoter are dispensable, a V(H) promoter and the intronic IgH enhancer region are not sufficient, and a region(s) within or 3' of the IgH constant region locus is requisite, for hypermutation of Ig V(H) transgenes.