Identification of a non-mammalian leptin-like gene:: Characterization and expression in the tiger salamander (Ambystoma tigrinum)
Identification of a non-mammalian leptin-like gene:: Characterization and expression in the tiger salamander (Ambystoma tigrinum)
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DOI：
10.1016/j.ygcen.2005.08.001
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发表时间：
2006-04-01
影响因子：
2.7
通讯作者：
Sharp, PJ
中科院分区：
文献类型：
--
作者：
Boswell, T;Dunn, IC;Sharp, PJ
瘦素在哺乳动物中是一种多功能细胞因子。然而，人们对其他脊椎动物瘦素基因的进化知之甚少。最近发表的一组来自虎蝾螈（Ambystoma tigrinum）的ESTs包含一个与人类瘦素cDNA共享56%核苷酸序列的序列。为了证实EST在蝾螈体内的自然表达，我们利用蝾螈睾丸和胃mrna的RT-PCR扩增出409 bp的cDNA。与哺乳动物一样，cDNA编码序列预计编码169个氨基酸，成熟肽由146个残基组成。尽管蝾螈肽与哺乳动物瘦素的整体氨基酸同源性只有29%，但蝾螈肽和哺乳动物肽具有共同的结构特征。在编码外显子之间发现了一个内含子，证明该序列存在于蝾螈基因组中。系统发育分析显示分子分化率与脊椎动物进化的公认观点一致。瘦素样cDNA的组织表达模式在不同大小的变态成年个体之间存在差异，提示可能存在发育调控。在技能和睾丸中表达最为突出，但在哺乳动物中也检测到瘦素mRNA存在的疾病组织，包括脂肪体、胃和肌肉。蝾螈瘦素样基因的鉴定为了解瘦素的结构和功能在四足脊椎动物进化过程中的变化提供了基础。(c) 2006爱思唯尔公司版权所有。
Leptin is well established as a multifunctional cytokine in mammals. However, little is known about the evolution of the leptin gene in other vertebrates. A recently published set of ESTs from the tiger salamander (Ambystoma tigrinum) contains a sequence sharing 56% nucleotide sequence identity with the human leptin cDNA. To confirm that the EST is naturally expressed ill the salamander, a 409 bp cDNA was amplified by RT-PCR of salamander testis and stomach mRNAs. The coding sequence of the cDNA is predicted to encode 169 amino acids, and the mature peptide to consist of 146 residues, as in mammals. Although the overall amino acid identity with mammalian leptins is only 29%, the salamander and mammalian peptides share common structural features. An intron was identified between coding exons providing evidence that the sequence is present in the salamander genome. Phylogenetic analysis showed a rate of molecular divergence consistent with the accepted view of vertebrate evolution. The pattern of tissue expression of the leptin-like cDNA differed between metamorphosed adult individuals of different sizes suggesting possible developmental regulation. Expression was most prominent in the skill and testis, but was also detected ill tissues in which leptin mRNA is present in mammals, including the fat body, stomach, and Muscle. The characterization of a salamander leptin-like gene provides a basis for understanding how the Structure and functions of leptin have altered during the evolution of tetrapod vertebrates. (c) 2006 Elsevier Inc. All rights reserved.