Abstract：
Insulin-like growth factor-binding proteins (IGFBPs) play important roles in regulating growth and development by binding to IGF, where IGFBP-3 and IGFBP-5 are the main binding carriers of IGF in the circulation system. In the present study, the gene sequences of igfbp-3, igfbp-5a, and igfbp-5b were cloned from the liver of yellowtail kingfish (Seriola lalandi). The ORF sequences of igfbp-3, igfbp-5a, and igfbp-5b were 888, 801, and 804 bp in length, which encoded 295, 266, and 267 amino acids, respectively. The above three genes were widely expressed in yellowtail kingfish tissues, with igfbp-3 being the most highly expressed in the heart, brain, and gonads, while igfbp-5a and igfbp-5b were both most highly expressed in the liver and kidney. The expression levels of igfbp-3, igfbp-5a, and igfbp-5b were detected throughout the embryonic and larval stages, suggesting their roles in early development and growth regulation of yellowtail kingfish. Besides, igfbp-3 and igfbp-5a were significantly up-regulated in the liver under food deprivation and high-density rearing conditions, which was exactly opposite to the growth performance of yellowtail kingfish, implying that they may serve as biomarkers of adverse culture conditions. Overall, the above results initially identified the molecular characteristics of igfbp-3/-5a/-5b in yellowtail kingfish and implied that they might play important roles in the growth and development, providing a basis for further research on underlying regulatory mechanisms.
摘要：
胰岛素样生长因子结合蛋白(IGFBPs)通过与IGF结合在调节生长发育中发挥重要作用,其中IGFBP-3和IGFBP-5是IGF在循环系统中的主要结合载体。在本研究中,igfbp-3,igfbp-5a的基因序列,从黄尾金鱼（Seriolalalandi）的肝脏中克隆了igfbp-5b。igfbp-3，igfbp-5a的ORF序列，igfbp-5b的长度分别为888、801和804bp，编码295、266和267个氨基酸，分别。上述三个基因在黄尾金鱼组织中广泛表达，igfbp-3在心脏中表达最高，大脑,和性腺,而igfbp-5a和igfbp-5b在肝脏和肾脏中表达最高。igfbp-3，igfbp-5a的表达水平，在整个胚胎和幼虫阶段都检测到了igfbp-5b，提示它们在黄尾金鱼早期发育和生长调节中的作用。此外,在食物匮乏和高密度饲养条件下，肝脏中的igfbp-3和igfbp-5a显著上调，这与黄尾鱼的生长表现完全相反，这意味着它们可以作为不良培养条件的生物标志物。总的来说,以上结果初步确定了黄尾金鱼中igfbp-3/-5a/-5b的分子特征，并暗示它们可能在生长发育中起重要作用，为进一步研究底层监管机制提供依据。
