Brain-specific promoter/exon I.f of the cyp19a1 (aromatase) gene in Xenopus laevis
Brain-specific promoter/exon I.f of the cyp19a1 (aromatase) gene in Xenopus laevis
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DOI：
10.1016/j.jsbmb.2012.05.007
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发表时间：
2012-11-01
影响因子：
4.1
通讯作者：
Iwabuchi, Junshin
中科院分区：
文献类型：
--
作者：
Nakagawa, Tadahiko;Iwabuchi, Junshin
cyp 19 a1基因编码的芳香化酶是雌激素生物合成的关键酶。非洲爪蟾脑芳香化酶转录本外显子I.f以脑特异性方式驱动。本研究利用S '-RACE技术克隆了脑芳香化酶基因，并检测了芳香化酶mRNA的表达模式。在爪蟾幼虫阶段，脑芳香化酶mRNA的表达是5倍高于性腺和肝脏，并上调阶段42至阶段50。在分离出位于性腺特异性外显子PII上游6.5 kb处的脑特异性启动子IS后，我们观察到该启动子是几种转录因子的潜在顺式元件，如Oct-1，c-Myc，加塔基因家族，C/EBPalpha，Sox 5，p300，XFD-1，AP 1，STAT基因家族。FOXD 3和Smad基因家族。此外，在5 '-RACE产物周围发现了两个启动子的核心启动子元件和一个非典型的TATA盒。在外显子If的5 '侧翼区，核提取物的结合位点表明以下是重要的：STAT基因家族，一个38 bp的保守区域在五个物种中，FOXD 3，和Smad基因家族在转录起始位点上游200 bp的区域内。实时定量RT-PCR分析表明foxd 3、smad 2和smad4.1/4.2 mRNA在脑中特异性表达。此外，已被报道为阻遏物的foxd 3的表达变化表明，与芳香化酶mRNA的表达相反，其表达从42期降低到50期。这些结果可能意味着foxd 3表达减少和芳香化酶表达增加的结果，作为一个转录激活因子，如smads的贡献启动子I.f。然而，由于这些假定的顺式元件和转录起始位点在其他物种的脑特异性启动子中不保守，因此外显子I.f的这种转录调控机制可能是非洲爪蟾的特征。(C)2012爱思唯尔有限公司保留所有权利。
Aromatase, encoded by the cyp19a1 gene, is the key enzyme for estrogen biosynthesis. Exon I.f of aromatase transcripts in the Xenopus brain is driven in a brain-specific manner. In this study, we cloned brain aromatase with a 5'-end of various lengths by S'-RACE and detected the expression pattern of the aromatase mRNA. In Xenopus at the larval stage, the brain aromatase mRNA expression was five-fold higher than those in the gonad and liver, and was upregulated from stage 42 to stage 50. After isolating the brain-specific promoter IS, which was located similar to 6.5 kb upstream from gonad-specific exon PII, we observed this promoter in a potential cis-elements for several transcriptional factors, such as Oct-1, c-Myc, the GATA gene family, C/EBPalpha, Sox5, p300, XFD-1, AP1, the STAT gene family. FOXD3, and the Smad gene family. In addition, the core promoter elements of two initiators and an atypical TATA box were found around the 5'-RACE products. In the 5'-flanking region of exon If, the binding sites for nuclear extracts suggested that the followings are important: the STAT gene family, a 38-bp conserved region among five species, FOXD3, and the Smad gene family within the region 200 bp upstream from the transcription initiation site. Real-time RT-PCR analysis showed that the foxd3, smad2 and smad4.1/4.2 mRNAs are specifically expressed in the brain. Furthermore, the expression change of foxd3, which has been reported as a repressor, indicated that expression decreased to stage 50 from stage 42, contrary to that of aromatase mRNA. These results may imply that foxd3 expression decreases and aromatase expression increases as a result of the contribution to promoter I.f by transcriptional activators such as smads. However, since these putative cis-elements and transcription initiation sites are not conserved in the brain-specific promoter of other species, this transcriptional regulatory mechanism of exon I.f may be characteristic of Xenopus. (C) 2012 Elsevier Ltd. All rights reserved.