cAMP-responsive element in TATA-less core promoter is essential for haploid-specific gene expression in mouse testis
cAMP-responsive element in TATA-less core promoter is essential for haploid-specific gene expression in mouse testis
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DOI：
10.1093/nar/gki652
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发表时间：
2005-01-01
影响因子：
14.9
通讯作者：
Nozaki, M
中科院分区：
文献类型：
--
作者：
Somboonthum, P;Ohta, H;Nozaki, M
启动子（既不包括TATA盒也不包括启动子）经常在小鼠睾丸生殖细胞特异性基因中发现。这些调查表明，独特形式的聚合酶II转录起始机制在精子发生过程中选择性激活生殖细胞特异性基因表达程序中发挥作用。然而，由于缺乏有效的生殖细胞培养系统，睾丸特异性核心启动子的研究还很少。在这项研究中，我们的特点的调节区的单倍体特异性Oxct 2b基因的详细使用在体内瞬时转染试验结合转基因的方法，电泳迁移率变化和染色质免疫沉淀试验。使用突变体构建体的表达研究表明，从-49延伸至-16的34 bp区域以取向依赖性方式充当核心启动子。该启动子区包括cAMP反应元件（CRE）样序列TGACGCAG，但不含其他基序，如TATA盒或启动子。CRE样元件是核心启动子活性不可或缺的，但不是睾丸生殖细胞中的激活剂，通过结合睾丸特异性CRE调节转录因子。这些结果表明，睾丸生殖细胞中存在细胞类型特异性基因表达的替代转录起始机制。
Promoters, including neither TATA box nor initiator, have been frequently found in testicular germ cellspecific genes in mice. These investigations imply that unique forms of the polymerase II transcription initiation machinery play a role in selective activation of germ cell-specific gene expression programs during spermatogenesis. However, there is little information about testis-specific core promoters, because useful germ cell culture system is not available. In this study, we characterize the regulatory region of the haploid-specific Oxct2b gene in detail by using in vivo transient transfection assay in combination with a transgenic approach, with electrophoretic mobility shift and chromatin immunoprecipitation assays. Expression studies using mutant constructs demonstrate that a 34 bp region, which extends from -49 to -16, acts as a core promoter in an orientation-dependent manner. This promoter region includes the cAMP-responsive element (CRE)-like sequence TGACGCAG, but contains no other motifs, such as a TATA box or initiator. The CRE-like element is indispensable for the core promoter activity, but not for activator in testicular germ cells, through the binding of a testis-specific CRE modulator transcription factor. These results indicate the presence of alternative transcriptional initiation machinery for cell-type-specific gene expression in testicular germ cells.