Intron 1 GATA site enhances ALAS2 expression indispensably during erythroid differentiation.
Intron 1 GATA site enhances ALAS2 expression indispensably during erythroid differentiation.
复制标题
内含子 1 GATA 位点在红系分化过程中必不可少地增强 ALAS2 表达。
DOI：
10.1093/nar/gkw901
复制
发表时间：
2017-01-25
影响因子：
14.9
通讯作者：
Zhu X
中科院分区：
文献类型：
--
作者：
Zhang Y;Zhang J;An W;Wan Y;Ma S;Yin J;Li X;Gao J;Yuan W;Guo Y;Engel JD;Shi L;Cheng T;Zhu X
5-氨基乙酰酸合成酶2 （ALAS2）内含子1 GATA位点（int-1-GATA）的第一个内含子突变在x连锁铁母细胞性贫血（XLSA）谱系中被发现，强烈提示它可能是XLSA的因果突变。然而，在体内发育过程中，这个int-1-GATA位点的功能在很大程度上仍然未知。在这里，我们生成了缺失13bp片段的小鼠，包括这个int-1-GATA位点（TAGATAAAGCCCC），并发现半合子缺失导致由于缺乏ALAS2表达导致的严重贫血而导致胚胎致死表型，这表明该非编码序列对于ALAS2在体内的表达是必不可少的。进一步分析表明，该int-1-GATA位点将GATA位点锚定在内含子8 （int-8-GATA）和近端启动子上，形成一个远程环，通过至少包括GATA1、TAL1、LMO2、LDB1和Pol II在内的增强子复合物，在红细胞中增强ALAS2的表达。然而，与int-8-GATA位点相比，int-1-GATA位点通过CRISPR/ cas9介导的位点特异性缺失来调节ALAS2的表达更为重要。因此，在未知突变的情况下，int-1-GATA位点可以作为诊断XLSA的有价值的位点。
The first intronic mutations in the intron 1 GATA site (int-1-GATA) of 5-aminolevulinate synthase 2 (ALAS2) have been identified in X-linked sideroblastic anemia (XLSA) pedigrees, strongly suggesting it could be causal mutations of XLSA. However, the function of this int-1-GATA site during in vivo development remains largely unknown. Here, we generated mice lacking a 13 bp fragment, including this int-1-GATA site (TAGATAAAGCCCC) and found that hemizygous deletion led to an embryonic lethal phenotype due to severe anemia resulting from a lack of ALAS2 expression, indicating that this non-coding sequence is indispensable for ALAS2 expression in vivo. Further analyses revealed that this int-1-GATA site anchored the GATA site in intron 8 (int-8-GATA) and the proximal promoter, forming a long-range loop to enhance ALAS2 expression by an enhancer complex including GATA1, TAL1, LMO2, LDB1 and Pol II at least, in erythroid cells. However, compared with the int-8-GATA site, the int-1-GATA site is more essential for regulating ALAS2 expression through CRISPR/Cas9-mediated site-specific deletion. Therefore, the int-1-GATA site could serve as a valuable site for diagnosing XLSA in cases with unknown mutations.