The Rheb-mTORC1 Coordinates Cell Cycle Progression and Endoreplication in <i>Bombyx mori</i>

The mechanistic target of the Rapamycin complex 1 (mTORC1) signaling pathway plays a pivotal role in regulating crucial life processes, including cell growth and proliferation, by sensing and integrating various signals, such as growth factors, energy status, and amino acids. Our previous studies sh...

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Main Authors: Zhangchen Tang, Huawei Liu, Qingsong Liu, Xin Tang, Jiahui Xu, Gan Luo, Qingyou Xia, Ping Zhao
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Insects
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Online Access:https://www.mdpi.com/2075-4450/16/7/647
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author Zhangchen Tang
Huawei Liu
Qingsong Liu
Xin Tang
Jiahui Xu
Gan Luo
Qingyou Xia
Ping Zhao
author_facet Zhangchen Tang
Huawei Liu
Qingsong Liu
Xin Tang
Jiahui Xu
Gan Luo
Qingyou Xia
Ping Zhao
author_sort Zhangchen Tang
collection DOAJ
description The mechanistic target of the Rapamycin complex 1 (mTORC1) signaling pathway plays a pivotal role in regulating crucial life processes, including cell growth and proliferation, by sensing and integrating various signals, such as growth factors, energy status, and amino acids. Our previous studies showed that activation of the mTORC1 signaling pathway enhances silk protein synthesis and silk gland size. Here, the potential of the molecular mechanism mTORC1 to regulate the growth and development of silk gland cells was investigated. Inhibiting mTORC1 with rapamycin decreased proliferation in the <i>Bombyx mori</i> embryonic (BmE) cells and endoreplication in silk gland cells, reducing CyclinB and CyclinE protein levels and DNA content, and arresting the BmE cell cycle at G2/M. Conversely, the overexpression of <i>Ras</i> homolog enriched in brain (<i>Rheb</i>) led to increased proliferation of BmE cells and endoreplication in silk gland cells, as well as a significant elevation in DNA content. This study provides a molecular explanation for the increase in silk protein synthesis and silk gland length through the activation of mTORC1, thereby refining the regulatory network of the silkworm endoreplication and providing new molecular targets for breeding high-yield varieties of <i>Bombyx mori</i>.
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institution Kabale University
issn 2075-4450
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series Insects
spelling doaj-art-d1e6cb2aa3504401bcf6007dce404dc52025-08-20T03:35:37ZengMDPI AGInsects2075-44502025-06-0116764710.3390/insects16070647The Rheb-mTORC1 Coordinates Cell Cycle Progression and Endoreplication in <i>Bombyx mori</i>Zhangchen Tang0Huawei Liu1Qingsong Liu2Xin Tang3Jiahui Xu4Gan Luo5Qingyou Xia6Ping Zhao7Integrative Science Center of Germplasm Creation in Western China (Chongqing) Science City, Biological Science Research Center, Southwest University, Chongqing 400715, ChinaIntegrative Science Center of Germplasm Creation in Western China (Chongqing) Science City, Biological Science Research Center, Southwest University, Chongqing 400715, ChinaIntegrative Science Center of Germplasm Creation in Western China (Chongqing) Science City, Biological Science Research Center, Southwest University, Chongqing 400715, ChinaIntegrative Science Center of Germplasm Creation in Western China (Chongqing) Science City, Biological Science Research Center, Southwest University, Chongqing 400715, ChinaIntegrative Science Center of Germplasm Creation in Western China (Chongqing) Science City, Biological Science Research Center, Southwest University, Chongqing 400715, ChinaWanzhou Center for Animal Husbandry Industry Development of Chongqing, Chongqing 404100, ChinaIntegrative Science Center of Germplasm Creation in Western China (Chongqing) Science City, Biological Science Research Center, Southwest University, Chongqing 400715, ChinaIntegrative Science Center of Germplasm Creation in Western China (Chongqing) Science City, Biological Science Research Center, Southwest University, Chongqing 400715, ChinaThe mechanistic target of the Rapamycin complex 1 (mTORC1) signaling pathway plays a pivotal role in regulating crucial life processes, including cell growth and proliferation, by sensing and integrating various signals, such as growth factors, energy status, and amino acids. Our previous studies showed that activation of the mTORC1 signaling pathway enhances silk protein synthesis and silk gland size. Here, the potential of the molecular mechanism mTORC1 to regulate the growth and development of silk gland cells was investigated. Inhibiting mTORC1 with rapamycin decreased proliferation in the <i>Bombyx mori</i> embryonic (BmE) cells and endoreplication in silk gland cells, reducing CyclinB and CyclinE protein levels and DNA content, and arresting the BmE cell cycle at G2/M. Conversely, the overexpression of <i>Ras</i> homolog enriched in brain (<i>Rheb</i>) led to increased proliferation of BmE cells and endoreplication in silk gland cells, as well as a significant elevation in DNA content. This study provides a molecular explanation for the increase in silk protein synthesis and silk gland length through the activation of mTORC1, thereby refining the regulatory network of the silkworm endoreplication and providing new molecular targets for breeding high-yield varieties of <i>Bombyx mori</i>.https://www.mdpi.com/2075-4450/16/7/647<i>Bombyx mori</i>cell cycleendoreplicationmTORC1Rhebsilk gland
spellingShingle Zhangchen Tang
Huawei Liu
Qingsong Liu
Xin Tang
Jiahui Xu
Gan Luo
Qingyou Xia
Ping Zhao
The Rheb-mTORC1 Coordinates Cell Cycle Progression and Endoreplication in <i>Bombyx mori</i>
Insects
<i>Bombyx mori</i>
cell cycle
endoreplication
mTORC1
Rheb
silk gland
title The Rheb-mTORC1 Coordinates Cell Cycle Progression and Endoreplication in <i>Bombyx mori</i>
title_full The Rheb-mTORC1 Coordinates Cell Cycle Progression and Endoreplication in <i>Bombyx mori</i>
title_fullStr The Rheb-mTORC1 Coordinates Cell Cycle Progression and Endoreplication in <i>Bombyx mori</i>
title_full_unstemmed The Rheb-mTORC1 Coordinates Cell Cycle Progression and Endoreplication in <i>Bombyx mori</i>
title_short The Rheb-mTORC1 Coordinates Cell Cycle Progression and Endoreplication in <i>Bombyx mori</i>
title_sort rheb mtorc1 coordinates cell cycle progression and endoreplication in i bombyx mori i
topic <i>Bombyx mori</i>
cell cycle
endoreplication
mTORC1
Rheb
silk gland
url https://www.mdpi.com/2075-4450/16/7/647
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