人类免疫球蛋白λ基因的结构和表达。
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Vasicek TJ,莱德P
人类免疫球蛋白λ基因的结构和表达。
J Exp。1990年8月1日,172 (2):609 - 20。
- PubMed ID
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2115572 (在PubMed]
- 文摘
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我们确定两大区域的DNA序列的染色体22:包含C 33.7 kbλ复杂;和5.2 kb 5 '的功能重新安排λ基因从人类骨髓瘤,U266。这些序列分析揭示了人类Cλ的完整结构复杂,从没被第七Cλ地区可能编码Ke + Oz -λ蛋白质。七个不变区域组织串联阵列,每个之前是一个Jλ。λ1λ2λ3,λ7显然是活跃的基因,当λ4λλ5和6是伪基因。没有其他Jλ或Cλ周围的区域在60 kb区域Cλ复杂;然而,至少有四个lambda-like基因和λ假基因在人类基因组中。λ的基因似乎通过一系列的进化基因重复事件造成不平等的交换或基因高度保守的Cλ之间的转换区域mispaired染色体上。缺乏Alu序列在这个大片段DNA表明Cλ复杂导致最近放大的小Alu-free段的DNA。非常规重组之间重复序列包含λλ2和3可以放大的λ基因负责变量。 We also found a 1,377-bp open reading frame (ORF) located on the opposite strand in the region containing lambda 7. While this ORF is flanked by potential RNA splicing signals, we have no evidence that it is part of a functional gene. We also discovered a V lambda pseudogene, called psi V lambda 1, 3 kb upstream of the U266 lambda gene. Using primer extension analysis to map the transcription start in the human lambda gene, we have identified its initiation point 41 bp upstream of the initiation codon. Analysis of the lambda promoter reveals that it contains a TATAA box at position -29 relative to the transcription initiation site and an octamer sequence at -67. Computer analysis of 40 kb of DNA sequences surrounding the human lambda locus has revealed no sequences resembling the kappa or IgH transcriptional enhancers, nor have in vitro analyses for function revealed enhancer activity. A comparison of these results with those obtained in separate studies with transgenic mice point to a complex, developmentally linked mechanism of transcriptional activation.