The insulin/insulin-like growth factor signaling (IIS) pathway is well-known in regulation of cell growth and proliferation in vertebrates, while its role in invertebrates such as mollusks remains largely unknown. In this study, we performed an extensive multi-omics data mining and identified four insulin-like peptide genes, including ILP, MIRP3, MIRP3-like and ILP7, in the Pacific oyster, Crassostrea gigas. Their potential roles in growth regulation were further investigated using the selectively bred fast-growing C. gigas variety “Haida No.1”. Expression profiling and in situ hybridization of these insulin-like peptides suggested their distinct tissue-specific expression pattern, with dominant expression in the neural enrichment tissues such as labial palp, visceral ganglia, adductor muscle, and digestive gland. The expressions of insulin-like peptides were significantly altered by food abundance in a gene-specific fashion. The expression of ILP was reduced during fasting and increased after re-feeding, the expression of MIRP3 and ILP7 were generally induced during fasting and down-regulated after re-feeding, while the expression of MIRP3-like was firstly up-regulated and then down-regulated during the fasting and re-feeding process. Furthermore, the expressions of all four insulin-like peptide genes were significantly suppressed at low temperature, in accordance with the growth inhibition. These results indicated that all four insulin-like peptides would play critical but different roles in regulation of growth in the oysters. This work provides valuable information for further investigation on growth regulation mechanism in mollusks and molecular assisted breeding of growth with other production traits in the Pacific oyster.

胰岛素/胰岛素样生长因子信号转导（IIS）途径在脊椎动物细胞生长和增殖的调节中是众所周知的，而其在无脊椎动物如软体动物中的作用仍然未知。在这项研究中，我们进行了广泛的多组学数据挖掘，并在太平洋牡蛎Crassostrea gigas中鉴定了四个胰岛素样肽基因，包括ILP，MIRP3，MIRP3类和ILP7。使用选择性繁殖的快速生长的C. gigas品种“海达1号”进一步研究了它们在生长调节中的潜在作用。表达分析和原位这些胰岛素样肽的杂交表明它们具有独特的组织特异性表达模式，并在神经富集组织如阴唇掌，内脏神经节，内收肌和消化腺中占主导。食物丰度以基因特异性方式显着改变了胰岛素样肽的表达。禁食期间ILP的表达降低，而再次喂食后ILP的表达增加，通常在禁食期间诱导MIRP3和ILP7的表达，并在喂食后下调，而类似MIRP3的表达在禁食和重新喂食过程中首先被上调，然后被下调。此外，根据生长抑制，在低温下所有四个胰岛素样肽基因的表达均被显着抑制。这些结果表明，所有四种胰岛素样肽在调节牡蛎生长中将发挥关键但不同的作用。这项工作为进一步研究软体动物中的生长调节机制以及分子牡蛎在其他牡蛎生产特性方面的生长提供了有价值的信息。