Sequences in the Aγ-δ intergenic region are not required for stage-specific regulation of the human β-globin gene locus
Sequences in the Aγ-δ intergenic region are not required for stage-specific regulation of the human β-globin gene locus
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DOI：
10.1073/pnas.0634132100
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发表时间：
2003-03-18
影响因子：
11.1
通讯作者：
Flebbe-Rehwaldt, L
中科院分区：
文献类型：
--
作者：
Gaensler, KML;Zhang, ZM;Flebbe-Rehwaldt, L
人类β-珠蛋白基因座作为组织和发育阶段特异性基因表达的模型已被广泛研究。自然发生突变的结构图谱，包括转染和转基因研究，以及基因间转录本的最新发现表明，(A)gamma-delta 基因间区域存在顺式作用序列元件，参与调节 γ 和 β 珠蛋白基因表达。为了确定人β-珠蛋白基因簇的适当发育表达是否需要先前鉴定的(A)gamma-delta基因间区域中的序列，通过转移含有整个人β-珠蛋白基因座的酵母人工染色体来产生转基因小鼠。引入了 (A)gamma-delta S 基因间区域的三种不同缺失，包括 (i) 750 bp (A)gamma-delta 调控元件 ((A)gammae) 的缺失，(ii) 包含富含嘧啶序列和最近描述的基因间转录起始位点的 δ-珠蛋白基因上游 3.2 kb 的缺失，以及 (iii) 删除了包含大部分 (A)gamma-delta 珠蛋白基因间区域的 12.5 kb 片段。对携带这些缺失构建体的多个转基因系的分析表明，尽管删除了这些假定的调控序列，但ε-、γ-和β-珠蛋白基因的正常阶段特异性顺序表达得以保留。这些研究表明，个体发育过程中人类β-珠蛋白基因家族激活和沉默所需的调控序列位于这些基因的近端，并且紧邻人类γ-和β-珠蛋白基因的5'。
The human beta-globin locus has been extensively studied as a model of tissue and developmental stage-specific gene expression. Structural mapping of naturally occurring mutations, including transfection and transgenic studies, and the recent finding of intergenic transcripts have suggested that there are cis-acting sequence elements in the (A)gamma-delta intergenic region involved in regulating gamma- and beta-globin gene expression. To determine whether previously identified sequences in the (A)gamma-delta intergenic region are required for appropriate developmental expression of the human beta-globin gene cluster, transgenic mice were generated by transfer of yeast artificial chromosomes containing the entire human beta-globin locus. Three different deletions of the (A)gamma-delta S intergenic region were introduced, including (i) deletion of the 750-bp (A)gamma-delta regulatory element ((A)gammae), (ii) deletion of 3.2 kb upstream of the delta-globin gene encompassing pyrimidine-rich sequences and the recently described intergenic transcript initiation site, and (iii) deletion of a 12.5-kb fragment encompassing most of the (A)gamma-delta globin intergenic region. Analysis of multiple transgenic lines carrying these deletion constructs demonstrated that the normal stage-specific sequential expression of the epsilon-, gamma-, and beta-globin genes was preserved, despite deletion of these putative regulatory sequences. These studies suggest that regulatory sequences required for activation and silencing of the human beta-globin gene family during ontogeny reside proximally to the genes and immediately 5' to the human gamma- and beta-globin genes.