Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
Gene. 2013 Sep 15;527(1):376-83. doi: 10.1016/j.gene.2013.04.079. Epub 2013 May 13.
Repertoires of proteins and small peptides play numerous physiological roles as hormones, antimicrobial peptides, and cellular signaling factors. The beta-thymosins are a group of small acidic peptides involved in processes such as actin sequestration, neuronal development, wound healing, tissue repair, and angiogenesis. Recent characterization of the beta thymosins as immunological regulators in invertebrates led to our identification and characterization of a beta-thymosin homologue (Tβ) from Haliotis discus discus. The cDNA possessed an ORF of 132 bp encoding a protein of 44 amino acids with a molecular mass of 4977 Da. The amino acid sequence shows high identity with another molluskan beta-thymosin and has a characteristic actin binding motif (LKKTET) and glutamyl donors. Phylogenetic analysis showed a close relationship with molluskan homologues, as well as its distinct identity and common ancestral origin. Genomic analysis revealed a 3 exon-2 intron structure similar to the other homologues. In silico promoter analysis also revealed significant transcription factor binding sites, providing evidence for the expression of this gene under different cellular conditions, including stress or pathogenic attack. Tissue distribution profiling revealed a ubiquitous presence in all the examined tissues, but with the highest expression in mantle and hemocyte. Immune challenge with lipopolysaccharide, poly I:C and Vibrio parahemolyticus induced beta-thymosin expression in gill and hemocytes, affirming an immune-related role in invertebrates.
蛋白质和小肽的作用谱多种多样，如作为激素、抗菌肽和细胞信号因子。β-胸腺素是一组参与肌动蛋白隔离、神经元发育、伤口愈合、组织修复和血管生成等过程的小酸性肽。β-胸腺素最近在无脊椎动物中被鉴定为免疫调节剂，这促使我们鉴定和表征了来自盘鲍（Haliotis discus discus）的β-胸腺素同源物（Tβ）。cDNA 具有 132bp 的 ORF，编码 44 个氨基酸的蛋白质，分子量为 4977Da。该氨基酸序列与另一种软体动物β-胸腺素有很高的同源性，具有特征性的肌动蛋白结合基序（LKKTET）和谷氨酰基供体。系统发育分析表明与软体动物同源物密切相关，具有独特的身份和共同的祖先起源。基因组分析显示了与其他同源物相似的 3 个外显子-2 个内含子结构。计算机预测的启动子分析也揭示了重要的转录因子结合位点，为该基因在不同细胞条件下的表达提供了证据，包括应激或病原攻击。组织分布分析显示该基因在所有检测的组织中普遍存在，但在套膜和血细胞中的表达最高。用脂多糖、多聚 I:C 和副溶血弧菌对鲍进行免疫挑战，诱导鳃和血细胞中β-胸腺素的表达，这证实了其在无脊椎动物中具有免疫相关作用。
