Conserved structure, regulatory elements, and transcriptional regulation from the GATA-1 gene testis promoter.
Conserved structure, regulatory elements, and transcriptional regulation from the GATA-1 gene testis promoter.
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GATA-1 基因睾丸启动子的保守结构、调控元件和转录调控。
DOI：
10.1093/oxfordjournals.jbchem.a021581
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发表时间：
1997
影响因子：
2.7
通讯作者：
Yamamoto,M
中科院分区：
文献类型：
--
作者：
Onodera,K;Yomogida,K;Suwabe,N;Takahashi,S;Muraosa,Y;Hayashi,N;Ito,E;Gu,L;Rassoulzadegan,M;Engel,JD;Yamamoto,M
转录因子GATA-1首先在红系细胞中被发现，但后来被证明也在小鼠睾丸的支持细胞中表达。GATA-1在睾丸中的转录起始于不同的第一外显子(外显子IT)，而不是红系mRNA(转录自外显子IE)。为了解决GATA-1在支持细胞和红系细胞中的表达如何受到差异调控的问题，我们克隆并确定了大鼠和小鼠GATA-1基因的IT启动子的结构。通过将野生型和突变型报告基因分别与GATA因子表达载体共转染成纤维细胞和支持细胞，研究了转录调控机制(S)对IT外显子衍生基因合成的调控作用。在成纤维细胞中，GATA因子介导的激活需要IT启动子上的两个GATA结合位点：GATA-IT导向的报告基因表达只有在与GATA-1共转染后才被激活，这意味着GATA-1在睾丸中的转录激活可能至少部分地通过这些GATA调节元件介导。我们还发现，在原代培养和两种不同的Sertoli细胞系中，内源性GATA-1基因都是沉默的，并且GATA-1在Sertoli细胞中的强制表达不能解除共转GATA-IT报告基因的抑制。因此，GATA-IT启动子可能受控于Sertoli细胞中的调控网络，该网络既涉及对转录的正向调控，也涉及对转录的负调控，在IT启动子中发现的保守的GATA基序可能需要传递这些作用。
Transcription factor GATA-1 was first identified in erythroid cells, but was later shown to also be expressed in Sertoli cells of the mouse testis. GATA-1 transcription in testis initiates from a different first exon (exon IT) than the erythroid mRNA (transcribed from exon IE). To begin to address the question of how expression of GATA-1 might be differentially regulated in Sertoli and erythroid cells, we have cloned and determined the structure of the IT promoters of both the rat and mouse GATA-1 genes. The transcription regulatory mechanism(s) controlling the synthesis of exon IT-derived mRNA was investigated by transfection of wild-type and mutant reporter genes, with and without co-transfected GATA factor expression plasmids, into either fibroblasts or Sertoli cell lines. Two GATA binding sites in the IT promoter were found to be required for GATA factor-mediated activation in fibroblasts: GATA-IT-directed reporter gene expression was activated only after co-transfection with GATA-1, implying that transcriptional activation of GATA-1 in the testis might be at least partially mediated through these GATA regulatory elements. We also found that the endogenous GATA-1 gene was silent in primary culture and two different Sertoli cell lines, and that the repression of co-transfected GATA-IT reporter genes could not be relieved by forced expression of GATA-1 in Sertoli cells. Thus the GATA-IT promoter may be under the control of a regulatory network in Sertoli cells which involves both positive and negative regulation of transcription, and conserved GATA motifs found in the IT promoter may berequired for transducing these effects.