Sp1 and Sp3 activate the testis-specific histone H1t promoter through the H1t/GC-box.
Sp1 and Sp3 activate the testis-specific histone H1t promoter through the H1t/GC-box.
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Sp1 和 Sp3 通过 H1t/GC-box 激活睾丸特异性组蛋白 H1t 启动子。
DOI：
10.1002/jcb.10265
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
Grimes,SidneyR
中科院分区：
文献类型：
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作者：
Wilkerson,DonaldC;Wolfe,StevenA;Grimes,SidneyR
睾丸特异性连接体组蛋白H1 t基因仅在粗线期中晚期初级精母细胞中转录。基因的组织特异性表达在很大程度上通过位于近端启动子内的元件介导。先前在转基因动物中的工作表明，一个独特的40 bp启动子元件H1 t/TE是精母细胞特异性表达所必需的。H1 t/TE元件包含一个GC-盒，这是一个完美的共识结合位点的成员的Sp家族的转录因子。我们已经证明Sp1和Sp3存在于9天大和成年大鼠的睾丸细胞以及粗线期初级精母细胞和早期精子细胞中，并且它们可以与H1 t/GC盒结合。GC盒的突变降低了H1 t启动子活性。此外，GC盒内的CpG二核苷酸在基因转录的大鼠睾丸初级精母细胞中完全未甲基化，但在基因沉默的肝脏中甲基化。这些先前的研究支持了GC盒的重要性，并表明Sp转录因子有助于H1 t基因的表达。在这项研究中，我们发现Sp1和Sp3表达载体的共转染导致包括睾丸GC-2spd细胞在内的几种细胞系中组蛋白H1 t启动子活性的上调。然而，在39°C下生长的GC-2spd细胞中观察到非常低的H1 t启动子活性，这与在该升高的温度下生长的这些细胞中较低水平的Sp1和Sp3相关。在共转染的NIH 3 T3和C127 I细胞系中也观察到Sp1和Sp3对H1 t启动子的上调。另一方面，Sp1和Sp3表达载体的共转染不会导致细胞周期依赖性组蛋白H1 d启动子的活性上调。J.细胞。86：716-725，2002.© 2002 Wiley利斯公司
The testis‐specific linker histone H1t gene is transcribed exclusively in mid to late pachytene primary spermatocytes. Tissue specific expression of the gene is mediated in large part through elements located within the proximal promoter. Previous work in transgenic animals showed that a unique 40 bp promoter element designated H1t/TE is essential for spermatocyte‐specific expression. The H1t/TE element contains a GC‐box, which is a perfect consensus binding site for members of the Sp family of transcription factors. We have shown that Sp1 and Sp3 are present in testis cells from 9‐day‐old and adult rats and in pachytene primary spermatocytes and early spermatids and that they can bind to the H1t/GC‐box. Mutagenesis of the GC‐box reduced H1t promoter activity. Furthermore, a CpG dinucleotide within the GC‐box was totally unmethylated in rat testis primary spermatocytes where the gene is transcribed but it was methylated in liver where the gene is silenced. These previous studies supported the importance of the GC‐box and suggested that Sp transcription factors contribute to expression of the H1t gene. In this study, we show that co‐transfection of Sp1 and Sp3 expression vectors leads to an upregulation of histone H1t promoter activity in several cell lines including testis GC‐2spd cells. However, very low H1t promoter activity is seen in GC‐2spd cells grown at 39°C, which correlates with lower levels of Sp1 and Sp3 in these cells grown at this elevated temperature. Upregulation of the H1t promoter by Sp1 and Sp3 was also seen in cotransfected NIH3T3 and C127I cell lines. On the other hand, co‐transfection of the Sp1 and Sp3 expression vectors does not lead to upregulation of activity of the cell‐cycle dependent histone H1d promoter. J. Cell. Biochem. 86: 716–725, 2002. © 2002 Wiley‐Liss, Inc.