Human promoter mutations unveil Oct-1 and GATA-1 opposite action on Gfi1b regulation
Human promoter mutations unveil Oct-1 and GATA-1 opposite action on Gfi1b regulation
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DOI：
10.1007/s00277-009-0900-x
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发表时间：
2010-08-01
影响因子：
3.5
通讯作者：
Anguita, Eduardo
中科院分区：
文献类型：
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作者：
Hernandez, Aurora;Villegas, Ana;Anguita, Eduardo
生长因子非依赖性1b（Growth factor-independence 1b，Gfi 1b）是红系和巨核细胞发育所必需的锌指转录因子。为了更好地了解Gfi 1b的调控，并了解该基因在人类病理学中的表达水平的含义，我们在214例不同血液病患者中寻找了启动子点序列变异。我们发现了两个以前未知的先天性突变在进化保守的加塔和八聚体结合（Oct）转录因子位点。Oct位点突变也在患者的5名亲属中发现。加塔基序突变在体外使启动子活性降低了50%，而具有八聚体位点突变的纯合子患者显示血小板中Gfi 1b RNA增加了4 - 5倍。电泳迁移率变动分析表明，不同的蛋白质复合物结合到这两个网站，并减少了突变的结合。最后，我们发现加塔-1和Oct-1是每个复合物的主要成分。该研究为Gfi 1b的抑制提供了新的机制。这也是第一个报告的Gfi 1b突变与功能的影响;进一步的调查和随访将澄清这些突变在血液病的参与。
Growth factor-independence 1b (Gfi1b) is a zinc finger transcription factor essential for erythroid and megakaryocytic development. To better understand Gfi1b regulation and to know the implication of the level of expression of this gene in human pathology, we have searched for promoter punctual sequence variations in 214 patients with different hematological diseases. We found two previously unknown congenital mutations at evolutionary conserved GATA and octamer-binding (Oct) transcription factor sites. The Oct site mutation was also found in five relatives of the patient. The GATA motif mutation reduced promoter activity by 50% in vitro, while homozygous patients with the octamer site mutation showed a four-to-five times increase of Gfi1b RNA in platelets. Electrophoretic mobility shift analyses demonstrated that different protein complexes bind to both sites and that binding is reduced by the mutations. Finally, we found that GATA-1 and Oct-1 are the main components of each complex. This study provides evidences of a new mechanism for Gfi1b repression. This is also the first report of Gfi1b mutations with a functional implication; further investigation and follow-up will clarify the involvement of these mutations in hematological disease.