Structural analysis of the entire proopiomelanocortin gene of Xenopus laevis.
Structural analysis of the entire proopiomelanocortin gene of Xenopus laevis.
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非洲爪蟾整个阿片黑皮质素原基因的结构分析。
DOI：
10.1111/j.1432-1033.1991.tb16265.x
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Martens,GJ
中科院分区：
文献类型：
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作者：
Deen,PM;Terwel,D;Bussemakers,MJ;Roubos,EW;Martens,GJ
在垂体的中间部，原激素原黑色素皮质素（POMC）被组织特异性地加工成α -促黑素（α - msh）和其他多肽。在南非爪蟾爪蟾（xenopus laevus）中，这种激素介导了背景适应过程：α - MSH的释放导致动物变黑，而α - MSH释放的抑制导致蟾蜍变白。α - MSH释放升高与POMC基因转录率升高一致。本研究旨在寻找xenopuspomc基因中可能的转录调控元件。为此，测定并分析了POMC基因的完整核苷酸序列及其5′‐和3′‐两翼区域。xenopuspomc基因启动子包含几个可能是调控DNA元件的区域，因为它们与哺乳动物POMC基因启动子的相应区域相似。在大鼠POMC基因启动子中，许多这些区域代表蛋白质结合序列。除启动子序列和蛋白编码序列外，未发现爪蟾和人类POMC基因之间具有显著同源性的其他片段。xenopuspomc基因的内含子A包含一个简单序列（TATC）76和一个JH12重复元件，而3 ' -侧翼区域包含一个重复- EcoRI -单体- 2元件。将POMC基因的JH12序列与其他xenopusgenes的JH12序列进行比较，发现一个335 bp的一致序列，其两侧有一个30 bp的反向重复序列。这一JH12共识序列明显大于之前报道的JH12核心区。将xenopuspomc基因的内含子B与数据库序列比对，发现一个330 bp的新xenopusrepeat元件的一致序列，其两侧是一个近乎完美的反向重复。表明该元件可能是转座子样元件。
In the pars intermedia of the pituitary the prohormone proopiomelanocortin (POMC) is tissue‐specifically processed to, among other peptides, α‐melanotropin (αMSH). In the South African clawed toadXenopus laevisthis hormone mediates the process of background adaptation: release of α‐MSH causes darkening of the animal, while inhibition of α‐MSH release results in a pale toad. Elevated release of α‐MSH coincides with a higher rate of POMC gene transcription. The present study aims to find possible transcriptional regulatory elements in theXenopusPOMC gene. For that purpose the complete nucleotide sequence of the POMC gene and its 5′‐ and 3′‐flanking regions were determined and analyzed. TheXenopusPOMC gene promoter contains several regions which may be regulatory DNA elements in view of their similarity with corresponding regions of mammalian POMC gene promoters. In the rat POMC gene promoter, many of these regions represent protein‐binding sequences. Besides the promoter sequence and the protein‐coding sequences, no other segments with significant identity between theXenopusand human POMC genes were found. Intron A of theXenopusPOMC gene contains a simple sequence, (TATC)76, and a JH12 repetitive element, while the 3′‐flanking region contains a repetitive‐EcoRI‐monomer‐2 element. Comparison of the JH12 sequence of the POMC gene with JH12 sequences from otherXenopusgenes revealed a 335‐bp consensus sequence which is flanked by a 30‐bp inverted repeat. This JH12 consensus sequence is significantly larger than the previously reported JH12 core region. Alignment of intron B of theXenopusPOMC gene with database sequences revealed a consensus sequence of a novelXenopusrepetitive element of 330 bp flanked by a nearly perfect inverted repeat. indicating that this element may be a transposonlike element.