Switching to fast growth: the insulin-like growth factor (IGF) system in skeletal muscle of Atlantic salmon
Switching to fast growth: the insulin-like growth factor (IGF) system in skeletal muscle of Atlantic salmon
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DOI：
10.1242/jeb.024117
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发表时间：
2008-12-15
影响因子：
2.8
通讯作者：
Johnston, Ian A.
中科院分区：
文献类型：
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作者：
Bower, Neil I.;Li, Xuejun;Johnston, Ian A.
在这项研究中，我们描述了完整的编码序列的胰岛素样生长因子I（IGF-I），胰岛素样生长因子II（IGF-II），胰岛素样生长因子结合蛋白（IGFBP）1，2，4，5和6和IGFBP相关蛋白1（IGFBP-rP 1）的大西洋鲑鱼（萨尔莫salar L.）。我们还报告了IGFBP-2和IGFBP-5的两个基因旁系同源物的特征。在22天的限制性饲养（0天），以实现零增长，鱼喂饱，并在3，5，7，14，30和60天取样。使用实时定量RT-PCR确定了在快速肌节肌中参与IGF信号通路的基因的表达谱。从零到快速生长的转变特征为IGF-I和IGFBP-4的组成性上调，IGFBP-5.2的瞬时增加，以及IGFBP-2.1、IGF-II、IGF 2 R（IGF-II受体）和IGFR 1a（IGF-I受体a）的下调。IGFBP-2.2、IGFBP-5.1、IGFBP-6、IGFBP-rP 1和IGFR 1b的表达对进食几乎没有反应。肌细胞生成标记基因肌细胞生成素、MHC和MLC 2的表达在限饲条件下较高，在14天时达到峰值，与IGF-I表达的峰值相对应，在限饲条件下较低。IGFBP-4，其中包含一个假定的结缔组织定位信号，是唯一的IGFBP组成性上调后喂养，并与IGF-I的表达呈正相关。总之，这些数据表明，大西洋鲑鱼骨骼肌快速生长的转变涉及IGF-I，IGFBP-5.2和IGFBP-4的局部上调，IGFBP-2.1的下调。
In this study we describe the complete coding sequence for insulin-like growth factor I (IGF-I), insulin-like growth factor II (IGF-II), insulin-like growth factor binding protein (IGFBP) 1, 2, 4, 5 and 6 and IGFBP-related protein 1 (IGFBP-rP1) of Atlantic salmon (Salmo salar L.). We also report the characterisation of two gene paralogues of IGFBP-2 and IGFBP-5. Following 22 days restricted feeding (0d) to achieve zero growth, fish were fed to satiation and sampled at 3, 5, 7, 14, 30 and 60 days. Expression profiles for genes involved in the IGF signalling pathway in fast myotomal muscle were determined using real-time quantitative RT-PCR. The transition from zero to fast growth is characterised by constitutive upregulation of IGF-I and IGFBP-4, a transient increase in IGFBP-5.2, and downregulation of IGFBP-2.1, IGF-II, IGF2R (IGF-II receptor) and IGFR1a (IGF-I receptor a). Expression of IGFBP-2.2, IGFBP-5.1, IGFBP-6, IGFBP-rP1 and IGFR1b showed little or no response to feeding. Expression of the myogenic marker genes myogenin, MHC and MLC2 were higher with feed restriction, and decreased as an early response to feeding, before increasing to a peak at 14 days, corresponding with a peak in IGF-I expression. IGFBP-4, which contains a putative connective tissue localisation signal, was the only IGFBP constitutively upregulated following feeding, and was positively correlated with IGF-I expression. Together, these data show that switching to fast growth in Atlantic salmon skeletal muscle involves the local upregulation of IGF-I, IGFBP-5.2 and IGFBP-4, with downregulation of IGFBP-2.1.