Thompson A, Timmers E, Schuurman R K, Hendriks R W
Department of Immunohaematology, University Hospital Leiden, The Netherlands.
Eur J Immunol. 1995 Jan;25(1):257-61. doi: 10.1002/eji.1830250142.
From human precursor B cells which had both immunoglobulin (Ig) heavy (H) chain loci in germ-line configuration, various IgH chain germ-line transcripts were isolated and sequenced. These transcripts were shown to contain sequences derived from the JH region, the IgH chain enhancer element or the Ig switch region. A number of isolated cDNA clones contained sequences at their 5' end that were derived from a single exon located just upstream of DQ52, designated the mu o' element. Sequence analysis of a 920-bp genomic DNA segment, containing the mu o' exon and its 5' flanking region, revealed the presence of various conserved motifs for DNA-binding proteins, such as E2A, Ets, NF-kappa B and AP-2, which have previously been found in the IgH and L chain enhancers. We propose that the activity of the mu o' element, resulting in germ-line transcription of the DQ52-JH gene segment, is required to generate full accessibility for the V(D)J recombinase.
从免疫球蛋白（Ig）重（H）链基因座均处于种系构型的人类前体B细胞中，分离并测序了各种IgH链种系转录本。这些转录本显示包含源自JH区域、IgH链增强子元件或Ig转换区域的序列。一些分离的cDNA克隆在其5'端含有源自位于DQ52上游的单个外显子的序列，命名为μo'元件。对一个包含μo'外显子及其5'侧翼区域的920 bp基因组DNA片段进行序列分析，发现了多种DNA结合蛋白的保守基序，如E2A、Ets、NF-κB和AP-2，这些基序先前已在IgH和L链增强子中发现。我们提出，μo'元件的活性导致DQ52-JH基因片段的种系转录，这是V（D）J重组酶产生完全可及性所必需的。
