Extremely high conservation in the untranslated region as well as the coding region of CNP mRNAs throughout elasmobranch species
Extremely high conservation in the untranslated region as well as the coding region of CNP mRNAs throughout elasmobranch species
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DOI：
10.1016/j.ygcen.2006.02.014
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发表时间：
2006-09-01
影响因子：
2.7
通讯作者：
Donald, John A.
中科院分区：
文献类型：
--
作者：
Hyodo, Susumu;Kawakoshi, Akatsuki;Donald, John A.
C型钠尿肽（CNP）是软骨鱼体内重要的渗透压调节激素，参与盐分分泌和饮水。与硬骨鱼和四足动物的 NP 家族由一组结构相关的肽组成相比，我们已经证明 CNP 是鲨鱼中唯一的 NT。在本研究中，从另一种软骨鱼类蝠鲼的四种物种中克隆了 CNP cDNA。克隆的 batoid CNP 前体含有 22 个氨基酸残基的合理成熟肽，与大多数鲨鱼 CNP-22 相同。但与鲨鱼前体相比，该片段中连续五个氨基酸被删除，支持鲨鱼和鳐鱼的二系分类。此外，CNP 前体的分子系统发育树与二系解释一致。除了缺失之外，CNP cDNA 的核苷酸和推导的氨基酸序列在所有软骨鱼物种中都极其保守，甚至在鲨鱼和鳐鱼之间也是如此。令人惊讶的是，不仅编码区具有明显的高度保守性，非翻译区也具有明显的高度保守性。高度保守很可能是由于软骨鱼类基因组中的低核苷酸取代率和高选择压力。软骨鱼 CNP cDNA 的 3'-非翻译区包含 ATTTA 基序的 3 至 6 个重复，该基序与 mRNA 稳定性和翻译效率的调节相关。还发现了替代的聚腺苷酸化位点；长的 3'-非翻译区包含 ATTTA 基序的核心，而短的形式只有一个或没有 ATTTA 基序。表明mRNA的转录后修饰对于CNP合成的调节很重要。 3'-非翻译区的这些特征在所有软骨鱼类 CNP cDNA 中都是保守的。由于 CNP 被认为是一种促进直肠腺盐分泌的速效激素，因此保守的 3'-非翻译区很可能有助于软骨鱼类中 CNP 合成的快速调节，以响应内部和外部环境的急剧变化。 (c) 2006 Elsevier Inc. 保留所有权利。
C-type natriuretic peptide (CNP) is a crucial osmoregulatory hormone in elasmobranchs, participating in salt secretion and drinking. In contrast to teleosts and tetrapods in which the NP family is composed of a group of structurally related peptides, we have shown that CNP is the sole NT in sharks. In the present study, CNP cDNAs were cloned from four species of batoids, another group of elasmobranchs. The cloned batoid CNP precursors contained a plausible mature peptide of 22 amino acid residues that is identical to most shark CNP-22s. but five successive amino acids were consistently deleted in the prosegment compared with shark precursors, supporting the diphyletic classification of sharks and rays. In addition, molecular phylogenetic trees of CNP precursors were consistent with a diphyletic interpretation. Except for the deletion, the nucleotide and deduced amino acid sequences of the CNP cDNAs are extremely well-conserved among all elasmobranch species, even between sharks and rays. Surprisingly, high conservation is evident not only for the coding region, but also for the untranslated regions. It is most likely that the high conservation is due to the low nucleotide substitution rate in the elasmobranch genome, and high selection pressure. The 3'-untranslated region of the elasmobranch CNP cDNAs contained three to six repeats of the ATTTA motif that is associated with the regulation of mRNA stability and translation efficiency. Alternative polyadenylation sites were also found; the long 3'-untranslated region contains a core of ATTTA motifs while the short form has only one or no ATTTA motif. indicating that the post-transcriptional modification of mRNA is important for regulation of CNP synthesis. These characteristics in the 3'-untranslated region were conserved among all elasmobranch CNP cDNAs. Since CNP has been implicated as a fast-acting hormone to facilitate salt secretion from the rectal gland, the conserved 3'-untranslated region most likely contributes to rapid regulation of CNP synthesis in elasmobranchs in response to acute changes in internal and external environments. (c) 2006 Elsevier Inc. All rights reserved.