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Yan J, Xue Z, Dong H, Pang J, Liu H, Gong J, Xia Q, Hou Y. Nutrition regulates the expression of storage proteins in Bombyx mori via insulin-like/FoxO signaling pathway. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2022; 149:103847. [PMID: 36155801 DOI: 10.1016/j.ibmb.2022.103847] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 09/12/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
Insect serum proteins, also termed storage proteins (SPs), are hexamer proteins that form amino acid reservoirs important for the development of pupae and embryos in most insects. In this study, we investigated the SP genes expression and regulation pathways in silkworms (Bombyx mori). We observed that B. mori SPs (BmSPs) in the fat body of larvae were strongly decreased by starvation, suggesting they respond to nutrition deprivation. Further, we examined the relationship between BmSP expression and the insulin-like signaling pathway (ILS) to study the regulation of BmSPs expression. The results showed that insulin up-regulated the expression of BmSPs, but an inhibitor of the ILS pathway protein PI3K downregulated the expression of BmSPs in B. mori larvae. Similar results were observed in cultured fat body in vitro and BmE cells. We then over-expressed FoxO, an ILS transcriptional factor, in BmE cells and B. mori larvae to further verify the regulatory role of ILS on expression of BmSPs and found BmFoxO negatively regulates the expression of BmSPs in both BmE cells and larvae. Moreover, BmFoxO was dephosphorylated and translocated from the cytoplasm to the nucleus under starvation treatment. Finally, an element on -2627-2644 bp upstream of the transcription start site of BmSP1 was identified as the binding site of BmFoxO by electrophoretic mobility shift assay and verified by chromatin immunoprecipitation. In summary, our results indicate that nutrient uptake triggers the expression of BmSPs via the ILS/FoxO signaling pathway. This study provides a reference for further study on the expression and regulation of insect SP genes.
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Affiliation(s)
- Jiamin Yan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing, 400715, China; Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China
| | - Zhao Xue
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing, 400715, China; Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China
| | - Haonan Dong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing, 400715, China; Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China
| | - Jiaxin Pang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing, 400715, China; Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China
| | - Huawei Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing, 400715, China; Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China
| | - Jing Gong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing, 400715, China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing, 400715, China; Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China; Chongqing Key Laboratory of Sericulture, Southwest University, Chongqing, 400716, China
| | - Yong Hou
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Beibei, Chongqing, 400715, China; Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China; Chongqing Key Laboratory of Sericulture, Southwest University, Chongqing, 400716, China.
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