1
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Hu W, Peng Z, Lv J, Zhang Q, Wang X, Xia Q. Developmental and nuclear proteomic signatures characterize the temporal regulation of fibroin synthesis during the last molting-feeding transition of silkworm. Int J Biol Macromol 2024; 274:133028. [PMID: 38857725 DOI: 10.1016/j.ijbiomac.2024.133028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 06/05/2024] [Accepted: 06/06/2024] [Indexed: 06/12/2024]
Abstract
Silkworm fibroins are natural proteinaceous macromolecules and provide core mechanical properties to silk fibers. The synthesis process of fibroins is posterior silk gland (PSG)-exclusive and appears active at the feeding stage and inactive at the molting stage. However, the molecular mechanisms controlling it remain elusive. Here, the silk gland's physiological and nuclear proteomic features were used to characterize changes in its structure and development from molting to feeding stages. The temporal expression profile and immunofluorescence analyses revealed a synchronous transcriptional on-off mode of fibroin genes. Next, the comparative nuclear proteome of the PSG during the last molting-feeding transition identified 798 differentially abundant proteins (DAPs), including 42 transcription factors and 15 epigenetic factors. Protein-protein interaction network analysis showed a "CTCF-FOX-HOX-SOX" association with activated expressions at the molting stage, suggesting a relatively complex and multifactorial regulation of the PSG at the molting stage. In addition, FAIRE-seq verification indicated "closed" and "open" conformations of fibroin gene promoters at the molting and feeding stages, respectively. Such proteome combined with chromatin accessibility analysis revealed the detailed signature of protein factors involved in the temporal regulation of fibroin synthesis and provided insights into silk gland development as well as silk production in silkworms.
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Affiliation(s)
- Wenbo Hu
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400715, China.
| | - Zhangchuan Peng
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400715, China; Chongqing Institute of Advanced Pathology, Jinfeng Laboratory, Chongqing 401329, China
| | - Jinfeng Lv
- Institute for Silk and Related Biomaterials Research, Chongqing Academy of Animal Sciences, Chongqing 402460, China
| | - Quan Zhang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400715, China
| | - Xiaogang Wang
- School of Basic Medical Science, Chongqing College of Traditional Chinese Medicine, Chongqing 400065, China
| | - Qingyou Xia
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400715, China.
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2
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Tao C, Li J, Du W, Qin X, Cao J, Liu C, Cheng T. Broad Complex-Z2 directly activates BmMBF2 to inhibit the silk protein synthesis in the silkworm, Bombyx mori. Int J Biol Macromol 2024; 277:134211. [PMID: 39069049 DOI: 10.1016/j.ijbiomac.2024.134211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 06/27/2024] [Accepted: 07/25/2024] [Indexed: 07/30/2024]
Abstract
Silk proteins, as natural macromolecules, have extensive applications in biomaterials and biomedicine. In the silkworm, the expression of silk protein genes is negatively associated with ecdysone during the molt stage, while it is positively correlated with juvenile hormone during the intermolt stage. In our previous study, overexpression of an isoform Z2 of Broad Complex (BmBrC-Z2), an ecdysone early response factor, significantly reduced the expression of silk protein genes. However, the underlying regulatory mechanism remains unclear. In this study, we conducted transcriptomic analysis and found that overexpressing BmBrC-Z2 significantly upregulated the expression level of multiprotein bridging factor 2 (BmMBF2), an inhibitor of fibroin heavy chain (FibH). Further investigations revealed that BmBrC-Z2 directly regulated BmMBF2 by binding to cis-regulatory elements, as demonstrated using Dual-Luciferase Reporter Gene Assay, EMSA, and ChIP-PCR assay. Additionally, when using the CRISPR/Cas9 system to knock out BmMBF2, silk protein genes were significantly upregulated during the molt stage of mutant larvae. These findings uncover the negative regulation of silk protein synthesis by the ecdysone signaling cascade, specifically through the manipulation of BmMBF2 expression during the molt stage. This study enhances to our understanding of the temporal regulatory mechanism governing silk protein synthesis and offers a potential strategy for improving silk yield.
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Affiliation(s)
- Cuicui Tao
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400715, China
| | - Jiaojiao Li
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400715, China
| | - Wenjie Du
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400715, China
| | - Xiaodan Qin
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400715, China
| | - Jun Cao
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400715, China
| | - Chun Liu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400715, China.
| | - Tingcai Cheng
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400715, China.
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3
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Ma Y, Li Q, Tang Y, Zhang Z, Liu R, Luo Q, Wang Y, Hu J, Chen Y, Li Z, Zhao C, Ran Y, Mu Y, Li Y, Xu X, Gong Y, He Z, Ba Y, Guo K, Dong K, Li X, Tan W, Zhu Y, Xiang Z, Xu H. The architecture of silk-secreting organs during the final larval stage of silkworms revealed by single-nucleus and spatial transcriptomics. Cell Rep 2024; 43:114460. [PMID: 38996068 DOI: 10.1016/j.celrep.2024.114460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/26/2024] [Accepted: 06/22/2024] [Indexed: 07/14/2024] Open
Abstract
Natural silks are renewable proteins with impressive mechanical properties and biocompatibility that are useful in various fields. However, the cellular and spatial organization of silk-secreting organs remains unclear. Here, we combined single-nucleus and spatially resolved transcriptomics to systematically map the cellular and spatial composition of the silk glands (SGs) of mulberry silkworms late in larval development. This approach allowed us to profile SG cell types and cell state dynamics and identify regulatory networks and cell-cell communication related to efficient silk protein synthesis; key markers were validated via transgenic approaches. Notably, we demonstrated the indispensable role of the ecdysone receptor (ultraspiracle) in regulating endoreplication in SG cells. Our atlas presents the results of spatiotemporal analysis of silk-secreting organ architecture late in larval development; this atlas provides a valuable reference for elucidating the mechanism of efficient silk protein synthesis and developing sustainable products made from natural silk.
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Affiliation(s)
- Yan Ma
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Qingjun Li
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Yiyun Tang
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Zhiyong Zhang
- Beijing SeekGene BioSciences Co., Ltd., Beijing 102206, China
| | - Rongpeng Liu
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Qin Luo
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Yuting Wang
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Jie Hu
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Yuqin Chen
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Zhiwei Li
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Chen Zhao
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Yiting Ran
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Yuanyuan Mu
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Yinghao Li
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Xiaoqing Xu
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Yuyan Gong
- Beijing SeekGene BioSciences Co., Ltd., Beijing 102206, China
| | - Zihan He
- Beijing SeekGene BioSciences Co., Ltd., Beijing 102206, China
| | - Yongbing Ba
- Shanghai OE Biotech. Co., Ltd., Shanghai 201212, China
| | - Kaiqi Guo
- Shanghai OE Biotech. Co., Ltd., Shanghai 201212, China
| | - Keshu Dong
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Xiao Li
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Wei Tan
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Yumeng Zhu
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Zhonghuai Xiang
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China
| | - Hanfu Xu
- State Key Laboratory of Resource Insects, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing 400715, China.
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4
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Masuoka Y, Jouraku A, Tsubota T, Ono H, Chiba H, Sezutsu H, Bono H, Yokoi K. Time-course transcriptome data of silk glands in day 0-7 last-instar larvae of Bombyx mori (w1 pnd strain). Sci Data 2024; 11:709. [PMID: 38942767 PMCID: PMC11213855 DOI: 10.1038/s41597-024-03560-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 06/20/2024] [Indexed: 06/30/2024] Open
Abstract
Time-course transcriptome expression data were constructed for four parts of the silk gland (anterior, middle, and posterior parts of the middle silk gland, along with the posterior silk gland) in the domestic silkworm, Bombyx mori, from days 0 to 7 of the last-instar larvae. For sample preparation, silk glands were extracted from one female and one male larva every 24 hours accurately after the fourth ecdysis. The reliability of these transcriptome data was confirmed by comparing the transcripts per million (TPM) values of the silk gene and quantitative reverse transcription PCR results. Hierarchical cluster analysis results supported the reliability of transcriptome data. These data are likely to contribute to the progress in molecular biology and genetic research using B. mori, such as elucidating the mechanism underlying the massive production of silk proteins, conducting entomological research using a meta-analysis as a model for lepidopteran insect species, and exploring medical research using B. mori as a model for disease species by utilising transcriptome data.
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Affiliation(s)
- Yudai Masuoka
- Insect Design Technology Group, Division of Insect Advanced Technology, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan
- Research Center for Agricultural Information Technology (RCAIT), National Agriculture and Food Research Organization (NARO), 1-31-1 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan
| | - Akiya Jouraku
- Insect Design Technology Group, Division of Insect Advanced Technology, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan
| | - Takuya Tsubota
- Silkworm Research Group, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan
| | - Hiromasa Ono
- Database Center for Life Science (DBCLS), Joint Support-Center for Data Science Research, Research Organization of Information and Systems, 178-4-4 Wakashiba, Kashiwa, Chiba, 277-0871, Japan
- Laboratory of BioDX, PtBio Co-Creation Research Center, Genome Editing Innovation Center, Hiroshima University, 3-10-23 Kagamiyama, Higashi-Hiroshima city, Hiroshima, 739-0046, Japan
- PtBio Inc., 3-10-23 Kagamiyama, Higashi-Hiroshima city, Hiroshima, 739-0046, Japan
| | - Hirokazu Chiba
- Database Center for Life Science (DBCLS), Joint Support-Center for Data Science Research, Research Organization of Information and Systems, 178-4-4 Wakashiba, Kashiwa, Chiba, 277-0871, Japan
| | - Hideki Sezutsu
- Silkworm Research Group, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan
| | - Hidemasa Bono
- Database Center for Life Science (DBCLS), Joint Support-Center for Data Science Research, Research Organization of Information and Systems, 178-4-4 Wakashiba, Kashiwa, Chiba, 277-0871, Japan
- Laboratory of BioDX, PtBio Co-Creation Research Center, Genome Editing Innovation Center, Hiroshima University, 3-10-23 Kagamiyama, Higashi-Hiroshima city, Hiroshima, 739-0046, Japan
- Laboratory of Genome Informatics, Graduate School of Integrated Sciences for Life, Hiroshima University, 3-10-23 Kagamiyama, Higashi-Hiroshima city, Hiroshima, 739-0046, Japan
| | - Kakeru Yokoi
- Insect Design Technology Group, Division of Insect Advanced Technology, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan.
- Research Center for Agricultural Information Technology (RCAIT), National Agriculture and Food Research Organization (NARO), 1-31-1 Kannondai, Tsukuba, Ibaraki, 305-0856, Japan.
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5
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Liu S, Tian H, Xu Y, Wang H. Juvenile hormone regulates silk gene expression by m 6A RNA methylation. Cell Mol Life Sci 2023; 80:331. [PMID: 37870631 PMCID: PMC11071706 DOI: 10.1007/s00018-023-04996-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/21/2023] [Accepted: 10/01/2023] [Indexed: 10/24/2023]
Abstract
Juvenile hormone (JH) is an indispensable insect hormone that is critical in regulating insect development and physiology. N6-methyladenosine (m6A) is the most abundant modification of RNA that regulates RNA fate in eukaryotic organisms. However, the relationship between m6A and JH remains largely unknown. Here, we found that the application of a Juvenile hormone analog (JHA) extended the larval period of Bombyx mori and increased the weight and thickness of the cocoon. Interestingly, global transcriptional patterns revealed that m6A-related genes are specifically regulated by JHA in the posterior silk gland (PSG) that synthesizes the major component of cocoon silk. By transcriptome and m6A sequencing data conjointly, we discovered that JHA significantly regulated the m6A modification in the PSG of B. mori and many m6A-containing genes are related to nucleic acid binding, nucleus, and nucleobase-containing compound metabolism. Notably, 547 genes were significantly regulated by JHA at both the m6A modification and expression levels, especially 16 silk-associated genes, including sericin2, seroin1, Serine protease inhibitors 4 (BmSPI4), Serine protease inhibitors 5 (BmSPI5), and LIM domain-binding protein 2 (Ldb). Among them, 11 silk associated genes were significantly affected by METTL3 knockdown, validating that these genes are targets of m6A modification. Furthermore, we confirm that JHA directly regulates the expression of BmSPI4 and BmSPI5 through m6A modification of CDS regions. These results demonstrate the essential role of m6A methylation regulated by JH in PSG, and elucidate a novel mechanism by which JH affects silk gland development via m6A methylation. This study uncovers that m6A modification is a critical factor mediating the effect of JH in insects.
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Affiliation(s)
- Shuaiqi Liu
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Huan Tian
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yusong Xu
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Huabing Wang
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China.
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6
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Guo K, Dong Z, Zhang X, Chen Y, Li Y, Jiang W, Qin L, Zhang Y, Guo Z, Xia Q, Zhao P. Analysis of histomorphometric and proteome dynamics inside the silk gland lumen of Bombyx mori revealed the dynamic change of silk protein during the molt stage. Int J Biol Macromol 2023; 236:123926. [PMID: 36889618 DOI: 10.1016/j.ijbiomac.2023.123926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/18/2023] [Accepted: 02/28/2023] [Indexed: 03/08/2023]
Abstract
Silkworms spin different silks at different growth stages for specific purposes. The silk spun before the end of each instar is stronger than that at the beginning of each instar and cocoon silk. However, the compositional changes in silk proteins during this process are unknown. Consequently, we performed histomorphological and proteomic analyses of the silk gland to characterize changes from the instar end to the next instar beginning. The silk glands were collected on day 3 of third- and fourth-instar larvae (III-3 and IV-3) and the beginning of fourth-instar larvae (IV-0). Proteomic analysis identified 2961 proteins from all silk glands. Silk proteins P25 and Ser5 were significantly more abundant in III-3 and IV-3 than in IV-0, and many cuticular proteins and protease inhibitors increased significantly in IV-0 compared with III-3 and IV-3. This shift may cause mechanical property differences between the instar end and beginning silk. Using section staining, qPCR, and western blotting, we found for the first time that silk proteins were degraded first and then resynthesized during the molting stage. Furthermore, we revealed that fibroinase mediated the changes of silk proteins during molting. Our results provide insights into the molecular mechanisms of silk proteins dynamic regulation during molting.
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Affiliation(s)
- Kaiyu Guo
- Biological Science Research Center, Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Southwest University, 400715 Chongqing, China; Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, 400715 Chongqing, China; Engineering Laboratory of Sericultural and Functional Genome and Biotechnology, Development and Reform Commission, 400715 Chongqing, China
| | - Zhaoming Dong
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, 400715 Chongqing, China; Engineering Laboratory of Sericultural and Functional Genome and Biotechnology, Development and Reform Commission, 400715 Chongqing, China
| | - Xiaolu Zhang
- Biological Science Research Center, Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Southwest University, 400715 Chongqing, China; Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, 400715 Chongqing, China; Engineering Laboratory of Sericultural and Functional Genome and Biotechnology, Development and Reform Commission, 400715 Chongqing, China
| | - Yuqing Chen
- Biological Science Research Center, Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Southwest University, 400715 Chongqing, China
| | - Yi Li
- Biological Science Research Center, Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Southwest University, 400715 Chongqing, China; Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, 400715 Chongqing, China; Engineering Laboratory of Sericultural and Functional Genome and Biotechnology, Development and Reform Commission, 400715 Chongqing, China
| | - Wenchao Jiang
- Biological Science Research Center, Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Southwest University, 400715 Chongqing, China; Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, 400715 Chongqing, China; Engineering Laboratory of Sericultural and Functional Genome and Biotechnology, Development and Reform Commission, 400715 Chongqing, China
| | - Lixia Qin
- Biological Science Research Center, Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Southwest University, 400715 Chongqing, China; Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, 400715 Chongqing, China; Engineering Laboratory of Sericultural and Functional Genome and Biotechnology, Development and Reform Commission, 400715 Chongqing, China
| | - Yan Zhang
- Biological Science Research Center, Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Southwest University, 400715 Chongqing, China; Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, 400715 Chongqing, China; Engineering Laboratory of Sericultural and Functional Genome and Biotechnology, Development and Reform Commission, 400715 Chongqing, China
| | - Zhouguanrui Guo
- Biological Science Research Center, Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Southwest University, 400715 Chongqing, China
| | - Qingyou Xia
- Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, 400715 Chongqing, China; Engineering Laboratory of Sericultural and Functional Genome and Biotechnology, Development and Reform Commission, 400715 Chongqing, China
| | - Ping Zhao
- Biological Science Research Center, Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Southwest University, 400715 Chongqing, China; Key Laboratory for Germplasm Creation in Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, 400715 Chongqing, China; Engineering Laboratory of Sericultural and Functional Genome and Biotechnology, Development and Reform Commission, 400715 Chongqing, China.
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7
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Ma Y, Zeng W, Ba Y, Luo Q, Ou Y, Liu R, Ma J, Tang Y, Hu J, Wang H, Tang X, Mu Y, Li Q, Chen Y, Ran Y, Xiang Z, Xu H. A single-cell transcriptomic atlas characterizes the silk-producing organ in the silkworm. Nat Commun 2022; 13:3316. [PMID: 35680954 PMCID: PMC9184679 DOI: 10.1038/s41467-022-31003-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 05/30/2022] [Indexed: 01/07/2023] Open
Abstract
The silk gland of the domesticated silkworm Bombyx mori, is a remarkable organ that produces vast amounts of silk with exceptional properties. Little is known about which silk gland cells execute silk protein synthesis and its precise spatiotemporal control. Here, we use single-cell RNA sequencing to build a comprehensive cell atlas of the silkworm silk gland, consisting of 14,972 high-quality cells representing 10 distinct cell types, in three early developmental stages. We annotate all 10 cell types and determine their distributions in each region of the silk gland. Additionally, we decode the developmental trajectory and gene expression status of silk gland cells. Finally, we discover marker genes involved in the regulation of silk gland development and silk protein synthesis. Altogether, this work reveals the heterogeneity of silkworm silk gland cells and their gene expression dynamics, affording a deeper understanding of silk-producing organs at the single-cell level. The molecular underpinning of silk-producing organs is not well characterized. Here the authors use single-cell RNA sequencing to build an atlas of the silkworm silk gland and reveal the heterogeneity of silk gland cells.
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Affiliation(s)
- Yan Ma
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China
| | - Wenhui Zeng
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China
| | - Yongbing Ba
- Shanghai OE Biotech. Co., Ltd., Shanghai, 201212, China
| | - Qin Luo
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China
| | - Yao Ou
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China
| | - Rongpeng Liu
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China
| | - Jingwen Ma
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China
| | - Yiyun Tang
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China
| | - Jie Hu
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China
| | - Haomiao Wang
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China
| | - Xuan Tang
- Shanghai OE Biotech. Co., Ltd., Shanghai, 201212, China
| | - Yuanyuan Mu
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China
| | - Qingjun Li
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China
| | - Yuqin Chen
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China
| | - Yiting Ran
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China
| | - Zhonghuai Xiang
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China
| | - Hanfu Xu
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, 400715, China.
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8
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Huang J, Chen Y, Zhu J, Wang M, Tang S, Yi Y, Shen X. Bombyx mori miR-2845 represses the expression of fibroin light chain gene both in vitro and in vivo. PLoS One 2021; 16:e0261391. [PMID: 34914767 PMCID: PMC8675719 DOI: 10.1371/journal.pone.0261391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/30/2021] [Indexed: 12/03/2022] Open
Abstract
To study the regulatory function of Bombyx mori (B. mori) miRNAs (bmo-miR) on the expression of fibroin light chain gene (BmFib-L), the 3’UTR of BmFib-L mRNA was used as the target for online prediction of miRNAs from miRBase using RNAhybrid Software, and miR-2845 was screened out. First, the expression profiles of miR-2845 and BmFib-L in larvae of the 5th instar were analyzed by Real-time quantitative PCR (RT-qPCR). Then recombinant plasmids (pcDNA3.0-pre-miR-2845 and pGL3.0-BmFib-L) were constructed to use for the expression of miR-2845 and BmFib-L 3’UTR, respectively. Cellular-level functional verification of miR-2845 on BmFib-L was carried out using multiple experimental methods (including dual luciferase reporter vectors, artificially synthesized mimics and inhibitors, and target site mutations). Finally, in vivo functional verification was performed by injecting the recombinant vector in 5th instar larvae. BmFib-L expression levels were detected using RT-qPCR in the posterior silk glands (PSG) of the injected larvae. Results showed that the expression of miR-2845 increased between the 1st and 5th day in 5th instar larvae, but began to decline on the 5th day, while the expression of the target gene BmFib-L increased sharply. This suggests that miR-2845 and BmFib-L expression levels show opposing trends, implying a negative regulatory relationship. In BmN cells, miR-2845 significantly down-regulated the expression of BmFib-L; the inhibitory effect of miR-2845 on BmFib-L was disappeared after mutation of the targeting site on 3’UTR of BmFib-L; in individuals, miR-2845 significantly down-regulated BmFib-L expression levels. Our results provide new experimental data for clarifying the molecular regulation mechanism of silk protein expression.
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Affiliation(s)
- JingYi Huang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China.,Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, China
| | - YanHua Chen
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China.,Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, China
| | - Juan Zhu
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China.,Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, China
| | - MeiXian Wang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China.,Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, China
| | - ShunMing Tang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China.,Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, China
| | - YongZhu Yi
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China.,Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, China
| | - XingJia Shen
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China.,Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, China
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9
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Ma Y, Sun Q, Huang L, Luo Q, Zeng W, Ou Y, Ma J, Xu H. Genome-wide survey and characterization of transcription factors in the silk gland of the silkworm, Bombyx mori. PLoS One 2021; 16:e0259870. [PMID: 34762712 PMCID: PMC8584736 DOI: 10.1371/journal.pone.0259870] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 10/27/2021] [Indexed: 12/13/2022] Open
Abstract
Transcription factors (TFs) are key proteins that modulate gene transcription and thereby lead to changes in the gene expression profile and the subsequent alteration of cellular functions. In the silk gland (SG) of silkworm Bombyx mori, an important silk-producing insect, TFs are of vital importance in the regulation of silk protein synthesis in this organ. However, which TFs exist and express in the SG remains largely unknown. Here, we report the large-scale identification of TFs in the SG based on available full-length transcript sequences and the most recent version of silkworm genome data. In total, 348 candidate TFs were identified by strict filtration and were classified into 56 TF families. Chromosomal distribution, motif composition, and phylogenetic relationship analyses revealed the typical characteristics of these TFs. In addition, the expression patterns of 348 TFs in various tissues of B. mori, especially the SG of fourth-molt (4LM) and day-3 and day-4 fifth-instar (5L3D and 5L4D) larvae, were investigated based on public RNA-seq data and gene microarray data, followed by spatiotemporal verification of TF expression levels by quantitative real-time PCR (qRT-PCR). This report describes the first comprehensive analysis of TFs in the B. mori SG. The results can serve as a baseline for further studies of the roles of TFs in the B. mori SG.
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Affiliation(s)
- Yan Ma
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Qiwei Sun
- Department of Paediatrics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Lihua Huang
- Centre for Cardiovascular Genomics and Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Qin Luo
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Wenhui Zeng
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Yao Ou
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Jingwen Ma
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Hanfu Xu
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
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10
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Li G, Lan H, Lu Q, He C, Wei Y, Mo D, Qu D, Xu K. The JH-Met2-Kr-h1 pathway is involved in pyriproxyfen-induced defects of metamorphosis and silk protein synthesis in silkworms, Bombyx mori. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2021; 179:104980. [PMID: 34802530 DOI: 10.1016/j.pestbp.2021.104980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 10/19/2021] [Accepted: 10/23/2021] [Indexed: 06/13/2023]
Abstract
Environmental residues of pryriproxyfen, a juvenile hormone analogue (JHA) type pesticide, may have on unintended consequences on non-target insects. However, the mechanism of pyriproxyfen action and silk protein synthesis in silkworms has not been reported. In the present study, we treated the silkworms with trace pyriproxyfen (1 × 10-4 mg/L) and found that the silkworm larvae showed no obvious poisoning symptoms, while the development of silk glands and cocoon-forming function were both seriously damaged due to the accumulation of pyriproxyfen in posterior silk gland (PSG). The titer of the juvenile hormone (JH) was increased, whereas the content of 20-hydroxyecdysone (20E) was reduced in pyriproxyfen-exposed hemolymph. Met2 is a component of the JH receptor complex and JH can promote its phosphorylation. We found Met2 and SRC were up-regulated in the larval stage after pyriproxyfen exposure, the JH-Met2/SRC complex led to the up-regulation of downstream genes Kr-h1, and Dimm, and then specifically inhibited the transcription of Fib-H. Meanwhile, the transcription of ecdysone inducible transcription factor Br-C Z4 was also inhibited by pyriproxyfen and resulted in the defects of metamorphosis. In conclusion, the trace pyriproxyfen could affect the metamorphosis and silk protein synthesis through the Met2-mediated pathway. Our study provided new evidence that Met2 might be a potential target gene of JHA in Lepidoptera.
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Affiliation(s)
- Guoli Li
- College of Agriculture, Guangxi University, Nanning, Guangxi 530004, PR China
| | - Huangli Lan
- College of Agriculture, Guangxi University, Nanning, Guangxi 530004, PR China
| | - Qingyu Lu
- College of Agriculture, Guangxi University, Nanning, Guangxi 530004, PR China
| | - Chunhui He
- College of Agriculture, Guangxi University, Nanning, Guangxi 530004, PR China
| | - Yuting Wei
- College of Agriculture, Guangxi University, Nanning, Guangxi 530004, PR China
| | - Danmei Mo
- College of Agriculture, Guangxi University, Nanning, Guangxi 530004, PR China
| | - Dacai Qu
- College of Agriculture, Guangxi University, Nanning, Guangxi 530004, PR China; Sericulture Institute of Guangxi University, Guangxi University, Nanning, Guangxi 530004, PR China
| | - Kaizun Xu
- College of Agriculture, Guangxi University, Nanning, Guangxi 530004, PR China; Sericulture Institute of Guangxi University, Guangxi University, Nanning, Guangxi 530004, PR China; National Demonstration Center for Experimental Plant Science Education, College of Agriculture, Guangxi University, Nanning, Guangxi 530004, PR China.
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11
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New insights into the proteins interacting with the promoters of silkworm fibroin genes. Sci Rep 2021; 11:15880. [PMID: 34354143 PMCID: PMC8342599 DOI: 10.1038/s41598-021-95400-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/26/2021] [Indexed: 12/02/2022] Open
Abstract
The silkworm, Bombyx mori, is a silk-producing insect that has contributed greatly to human society. The silk gland of B. mori is a specialized organ responsible for synthesizing silk fibroin and sericin proteins under control of numerous factors. However, which factors are involved in direct silk protein synthesis regulation remains largely unknown. We report the identification of promoter-interacting proteins (PIPs) necessary for the regulation of genes encoding fibroin proteins, including the fibroin heavy chain (fibH), fibroin light chain (fibL), and a 25-kD polypeptide protein (P25). In the fourth larval molting stage (M4) or day 5 fifth-instar larvae (L5D5), a total of 198, 292, and 247 or 330, 305, and 460 proteins interacting with the promoter region of fibH, fibL and P25, respectively, were identified from the posterior silk gland by DNA pull-down combined with mass spectrometry. Many PIPs were particularly involved in ribosome- and metabolism-related pathways. Additionally, 135 and 212 proteins were identified as common PIPs of fibH, fibL and P25 in M4 and L5D5, respectively. Among all PIPs, we identified 31 potential transcription factors, such as Y-box and poly A-binding proteins, which play roles in nucleotide binding, ATP binding, or protein folding. This study provides the first in-depth profile of proteins interacting with fibroin gene promoters and contributes to a better understanding of silk protein synthesis regulation.
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12
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Cong J, Tao C, Zhang X, Zhang H, Cheng T, Liu C. Transgenic Ectopic Overexpression of Broad Complex ( BrC-Z2) in the Silk Gland Inhibits the Expression of Silk Fibroin Genes of Bombyx mori. INSECTS 2020; 11:insects11060374. [PMID: 32560131 PMCID: PMC7349191 DOI: 10.3390/insects11060374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/10/2020] [Accepted: 06/12/2020] [Indexed: 11/23/2022]
Abstract
Bombyx mori silk protein genes are strictly turned on and off in different developmental stages under the hormone periodically change. The broad complex (BrC) is a transcription factor mediating 20-hydroxyecdysone action, which plays important roles during metamorphosis. Here, we observed that two isoforms of BmBrC (BmBrC-Z2 and BmBrC-Z4) exhibited contrasting expression patterns with fibroin genes (FibH, FibL and P25) in the posterior silk gland (PSG), suggesting that BmBrC may negatively regulate fibroin genes. Transgenic lines were constructed to ectopically overexpress BmBrC-Z2 in the PSG. The silk protein genes in the transgenic line were decreased to almost half of that in the wild type. The silk yield was decreased significantly. In addition, the expression levels of regulatory factors (BmKr-h1 and BmDimm) response to juvenile hormone (JH) signal were inhibited significantly. Then exogenous JH in the BmBrC-Z2 overexpressed lines can inhibit the expression of BmBrC-Z2 and activate the expression of silk protein genes and restore the silk yield to the level of the wild type. These results indicated that BmBrC may inhibit fibroin genes by repressing the JH signal pathway, which would assist in deciphering the comprehensive regulation mechanism of silk protein genes.
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Affiliation(s)
| | | | | | | | | | - Chun Liu
- Correspondence: ; Tel.: +86-23-68251753; Fax: 86-23-68251128
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13
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Insights into the regulatory characteristics of silkworm fibroin gene promoters using a modified Gal4/UAS system. Transgenic Res 2019; 28:627-636. [DOI: 10.1007/s11248-019-00175-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 09/25/2019] [Indexed: 10/25/2022]
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14
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Hu W, Chen Y, Lin Y, Xia Q. Developmental and transcriptomic features characterize defects of silk gland growth and silk production in silkworm naked pupa mutant. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 111:103175. [PMID: 31150761 DOI: 10.1016/j.ibmb.2019.05.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 05/23/2019] [Accepted: 05/26/2019] [Indexed: 06/09/2023]
Abstract
The silkworm Bombyx mori is a well-characterized model organism for studying the silk gland development and silk production process. Using positional cloning and gene sequencing, we have previously reported that a truncated fibroin heavy chain was responsible for silkworm naked pupa (Nd) mutant. However, the mechanisms by which the mutant FibH causes developmental defects and secretion-deficiency of the silk gland remain to be fully elucidated. Here, silk gland's developmental features, histomorphology, and transcriptome analyses were used to characterize changes in its structure and gene expression patterns between Nd mutant and WT/Dazao. Whole larval stage investigation showed that Nd-PSG undergoes an arrested/delayed development, which eventually resulted in a gland degeneration. By using section staining and transmission electron microscope, a blockade in intracellular vesicle transport from endoplasmic reticulum to Golgi apparatus (secretion-deficiency) and an increased number of autophagosomes and lysosomes were found in Nd-PSG's cytoplasm. Next, by using RNA sequencing and comparative transcriptomic analysis, 2178 differentially expressed genes were identified between Nd-PSG and WT-PSG, among which most of the DEGs associated with cellular stress responses (autophagy, ubiquitin-proteasome system, and heat shock response) were significantly up-regulated in Nd-PSG, suggesting that mutant FibH perturbed cellular homeostasis and resulted in an activation of adaptive responses in PSG cells. These findings reveal the molecular mechanism of the Naked pupa (Nd) mutation and provide insights into silk gland development as well as silk protein production in silkworm Bombyx mori.
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Affiliation(s)
- Wenbo Hu
- Biological Science Research Center, Southwest University, Chongqing, 400716, PR China; Chongqing Key Laboratory of Sericulture Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Beibei, Chongqing, 400716, PR China
| | - Yulin Chen
- Biological Science Research Center, Southwest University, Chongqing, 400716, PR China; Chongqing Key Laboratory of Sericulture Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Beibei, Chongqing, 400716, PR China
| | - Ying Lin
- Biological Science Research Center, Southwest University, Chongqing, 400716, PR China; Chongqing Key Laboratory of Sericulture Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Beibei, Chongqing, 400716, PR China
| | - Qingyou Xia
- Biological Science Research Center, Southwest University, Chongqing, 400716, PR China; Chongqing Key Laboratory of Sericulture Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Beibei, Chongqing, 400716, PR China.
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15
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Chen Y, Bai B, Yan H, Wen F, Qin D, Jander G, Xia Q, Wang G. Systemic disruption of the homeostasis of transfer RNA isopentenyltransferase causes growth and development abnormalities in Bombyx mori. INSECT MOLECULAR BIOLOGY 2019; 28:380-391. [PMID: 30548717 DOI: 10.1111/imb.12561] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Isopentenylation at A37 (i6 A37) of some transfer RNAs (tRNAs) plays a vital role in regulating the efficiency and fidelity of protein synthesis. However, whether insects, which are well known for their highly efficient protein synthesis machinery, employ this regulatory mechanism remains uninvestigated. In the current study, a candidate tRNA isopentenyltransferase (IPT) gene with three alternative splicing isoforms (BmIPT1-BmIPT3) was identified in Bombyx mori (silkworm). Only BmIPT1 could complement a yeast mutant lacking tRNA IPT. Phylogenetic analysis showed that silkworm tRNA IPT is conserved in the Lepidoptera. BmIPT was expressed in all B. mori tissues and organs that were investigated, but was expressed at a significantly higher level in silk glands of the fourth instar compared to the first day of the fifth instar. Interestingly, BmIPT was expressed at a significantly higher level in the domesticated silkworm, B. mori, than in wild Bombyx mandarina in multiple tissues and organs. Knock-down of BmIPT by RNA interference caused severe abnormalities in silk spinning and metamorphosis. Constitutive overexpression of BmIPT1 using a cytoplasmic actin 4 promoter in B. mori raised its messenger RNA level more than sixfold compared with nontransgenic insects and led to significant decreases in the body weight and cocoon shell ratio. Together, these results confirm the first functional tRNA IPT in insects and show that a suitable expression level of tRNA IPT is vital for silk spinning, normal growth, and metamorphosis. Thus, i6 A modification at position A37 in tRNA probably plays an important role in B. mori protein synthesis.
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Affiliation(s)
- Y Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - B Bai
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - H Yan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - F Wen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - D Qin
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - G Jander
- Boyce Thompson Institute, Ithaca, NY, USA
| | - Q Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing, China
| | - G Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing, China
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16
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Liu L, Wang Y, Li Y, Ding C, Zhao P, Xia Q, He H. Cross-talk between juvenile hormone and ecdysone regulates transcription of fibroin modulator binding protein-1 in Bombyx mori. Int J Biol Macromol 2019; 128:28-39. [PMID: 30682471 DOI: 10.1016/j.ijbiomac.2019.01.092] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 01/18/2019] [Accepted: 01/18/2019] [Indexed: 01/05/2023]
Abstract
Juvenile hormone (JH) and 20-hydroxyecdysone (20E) are the most important hormones in silkworm and play vital roles in silkworm development, metamorphosis, and silk protein synthesis. Fibroin modulator binding protein-1 (FMBP-1) is a novel transcription factor regulating fibroin heavy chain (fib-H) transcription in Bombyx mori. The roles of JH and 20E on FMBP-1 transcription are less known. Here, we show FMBP-1 transcription is repressed by juvenile hormone analog (JHA) and activated by 20E. We identify two Krüppel homolog 1 (Kr-h1) binding sites (KBS1 and KBS2) and an E74A binding site (EBS) in the promoter of FMBP-1. We demonstrate Kr-h1 directly binds to KBS1 and KBS2 to repress FMBP-1 transcription, and 20E promotes FMBP-1 transcription through E74A. In the presence of JH and 20E, E74A abolishes the repression of Kr-h1 and activates FMBP-1 transcription through direct binding to EBS between KBS1 and KBS2 in FMBP-1 promoter. Further, JHA and 20E treatment and RNA interference confirm the effects of JH and 20E on FMBP-1 transcription in vivo, thus affecting fib-H transcription. Our results reveal the molecular mechanism of FMBP-1 transcription regulated by the cross-talk between JH and 20E in Bombyx mori, and provide novel insights into FMBP-1 transcriptional regulation and silk protein synthesis.
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Affiliation(s)
- Lina Liu
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China
| | - Yejing Wang
- College of Biotechnology, Southwest University, Beibei, Chongqing 400715, China.
| | - Yu Li
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China
| | - Chaoxiang Ding
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China
| | - Ping Zhao
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Beibei, Chongqing 400715, China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Beibei, Chongqing 400715, China
| | - Huawei He
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing 400715, China; Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Beibei, Chongqing 400715, China.
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17
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Liu L, Wang Y, Li Y, Guo P, Liu C, Li Z, Wang F, Zhao P, Xia Q, He H. Insights into the repression of fibroin modulator binding protein-1 on the transcription of fibroin H-chain during molting in Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 104:39-49. [PMID: 30543984 DOI: 10.1016/j.ibmb.2018.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 12/07/2018] [Accepted: 12/07/2018] [Indexed: 06/09/2023]
Abstract
Fibroin modulator binding protein-1 (FMBP-1) is a novel DNA-binding protein containing a conserved score and three amino acid peptide repeat (STPR) domain. The roles of factors containing STPR domain are less known. Although multiple transcription factors are involved in the transcriptional regulation of silk protein genes during the development of silkworm, the mechanism of transcriptional repression of silk protein genes during molting remains unclear. Here, we found that FMBP-1 expression was contrary to that of fibroin heavy chain (fib-H) during the fourth molting period of Bombyx mori. FMBP-1 repressed fib-H promoter activity by directly binding to the -130 element in the fib-H promoter region. We also identified two proteins, Bmsage and Bmdimm, that interacted with FMBP-1 in the posterior silk gland of silkworm larvae, and further verified these interactions by far western blotting and microscale thermophoresis in vitro, as well as co-immunoprecipitation and bimolecular fluorescence complementation at the cellular level. The luciferase reporter assay showed that the interaction between FMBP-1 and Bmdimm antagonized the activation of Bmdimm on fib-H transcription, but did not affect FMBP-1-mediated transcriptional repression on fib-H gene. Therefore, we proposed the following mechanism of fib-H transcriptional repression by FMBP-1 during the molting of silkworm larvae: 1) FMBP-1 directly binds to the -130 element in the fib-H promoter to repress fib-H transcription; 2) FMBP-1 interacts with Bmdimm to antagonize the activation of Bmdimm on fib-H transcription. Our findings promote a better understanding of fib-H transcriptional regulation and provide novel insights into the transcriptional repression of fib-H by FMBP-1 and basic helix-loop-helix factors Bmdimm during the molting of silkworm larvae. Our study also provides valuable information regarding the biological function of factors containing STPR domain.
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Affiliation(s)
- Lina Liu
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China
| | - Yejing Wang
- College of Biotechnology, Southwest University, Beibei, Chongqing, 400715, China.
| | - Yu Li
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China
| | - Pengchao Guo
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China
| | - Chun Liu
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China
| | - Zhiqing Li
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China
| | - Feng Wang
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China
| | - Ping Zhao
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China; Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Beibei, Chongqing, 400715, China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China; Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Beibei, Chongqing, 400715, China.
| | - Huawei He
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Beibei, Chongqing, 400715, China; Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Beibei, Chongqing, 400715, China.
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Qin S, Danso B, Zhang J, Li J, Liu N, Sun X, Hou C, Luo H, Chen K, Zhang G, Li M. MicroRNA profile of silk gland reveals different silk yields of three silkworm strains. Gene 2018; 653:1-9. [PMID: 29432827 DOI: 10.1016/j.gene.2018.02.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 01/27/2018] [Accepted: 02/07/2018] [Indexed: 12/15/2022]
Abstract
Silk proteins are synthesized and secreted by the silk gland. The differential gene expression in it leads to different silk yield among various silkworm strains. As crucial factors, microRNAs (miRNAs) regulate protein synthesis at post-transcriptional level in silk gland. MiRNAs expression level in the silk gland of three silkworm strains (Jingsong, Lan10 and Dazao) was analyzed and 33 differentially expressed miRNAs (DEMs) were discovered between JingSong (JS) and Lan10 (L10), 60 DEMs between JS and Dazao, 54 DEMs between L10 and Dazao respectively. The DEMs target genes were predicted combing with two different methods and their functions were annotated according to gene ontology. Our previous studies showed that a batch of genes related to silk yield were identified in JS and L10 strains by comparative transcriptome and quantitative trait loci (QTL) method. Thirteen DEMs whose target genes are related to protein biosynthesis processes were screened by combining with these researches. Twelve DEMs potentially regulate nineteen genes which exist in our QTL results. Six common DEMs potentially regulate the genes in both of previous results. Finally, five DEMs were selected to verify their expression levels between JS and L10 by qRT-PCR, which showed similar difference as the results of small RNA-sequencing. MiRNAs in the silk gland may directly affect silk protein biosynthesis in different silkworm strains. In current work, we identified a batch of DEMs which potentially regulate the genes related to silk yield. Further functionally study of these miRNAs will contribute to improve varieties and boost the silk yield. Our research provides a basis for studying these miRNAs and their functions in silk production.
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Affiliation(s)
- Sheng Qin
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, China; The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang, Jiangsu 212018, China.
| | - Blessing Danso
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, China
| | - Jing Zhang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, China
| | - Juan Li
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, China
| | - Na Liu
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, China
| | - Xia Sun
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, China
| | - Chengxiang Hou
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, China; The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang, Jiangsu 212018, China
| | - Heng Luo
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, China.
| | - Keping Chen
- Institute of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
| | - Guozheng Zhang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, China; The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang, Jiangsu 212018, China
| | - Muwang Li
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, China; The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang, Jiangsu 212018, China.
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Kweon H, Jo YY, Seok H, Kim SG, Chae WS, Sapru S, Kundu SC, Kim DW, Park NR, Che X, Choi JY. In vivo bone regeneration ability of different layers of natural silk cocoon processed using an eco-friendly method. Macromol Res 2017. [DOI: 10.1007/s13233-017-5085-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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20
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Li W, Cheng T, Hu W, Peng Z, Liu C, Xia Q. Genome-wide identification and analysis of JHBP-domain family members in the silkworm Bombyx mori. Mol Genet Genomics 2016; 291:2159-2171. [PMID: 27631967 DOI: 10.1007/s00438-016-1245-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/29/2016] [Indexed: 12/20/2022]
Abstract
Juvenile hormone (JH) regulates the insect growth and development. JH appears in the hemolymph bound by a specific glycoprotein, juvenile hormone-binding protein (JHBP), which serves as a carrier to release the hormone to target tissues and cells. However, JHBP family candidates, expression patterns, and functional implications are still unclear. In this study, we identified 41 genes-containing conserved JHBP domains distributed across eight chromosomes of the silkworm Bombyx mori. A phylogenetic tree showed that the silkworm JHBP (BmJHBP) genes could be classified into two major branches and four subfamilies. Microarray data revealed that BmJHBP genes exhibit various expression patterns and are expressed in different tissues, periods, and sexes. The expression of BmJHBP genes was generally higher in the head, integument, midgut, fat body, testis, and ovary than in the anterior of the silk gland (ASG), median of the silk gland (MSG), posterior of the silk gland (PSG), hemocyte, and Malpighian tubule. BmJHBPd2, in particular, was investigated by Western Blotting, and immunofluorescent assay and was found to be highly expressed in the PSG cytoplasm on day 3 of the fifth instar, coinciding with silk production. Taken together, our findings will be useful in improving understanding the complexity of the JHBP family, and will lay the foundation of explaining functional characterization for further research.
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Affiliation(s)
- Wei Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Tingcai Cheng
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Wenbo Hu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Zhangchuan Peng
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China
| | - Chun Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China. .,Chongqing Engineering and Technology Research Center for Novel Silk Materials, Chongqing, 400716, China.
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China.,Chongqing Engineering and Technology Research Center for Novel Silk Materials, Chongqing, 400716, China
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21
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Hu W, Liu C, Cheng T, Li W, Wang N, Xia Q. Histomorphometric and transcriptomic features characterize silk glands' development during the molt to intermolt transition process in silkworm. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2016; 76:95-108. [PMID: 27395780 DOI: 10.1016/j.ibmb.2016.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/20/2016] [Accepted: 07/05/2016] [Indexed: 06/06/2023]
Abstract
The molt-intermolt cycle is an essential feature in holometabolous and hemimetabolous insects' development. In the silkworm, silk glands are under dramatic morphological and functional changes with fibroin genes' transcription being repeatedly turned off and on during the molt-intermolt cycles. However, the molecular mechanisms controlling it are still unknown. Here, silk gland's histomorphology and transcriptome analysis were used to characterize changes in its structure and gene expression patterns from molt to intermolt stages. By using section staining and transmission electron microscope, a renewable cell damage was detected in the silk gland at the molt stage, and an increased number of autophagosomes and lysosomes were found in silk gland cells' cytoplasm. Next, by using RNA sequencing, 54,578,413 reads were obtained, of which 85% were mapped to the silkworm reference genome. The expression level analysis of silk protein genes and silk gland transcription factors revealed that fibroin heavy chain, fibroin light chain, P25/fhx, sericin1, sericin3 and Dimm had consistent alteration trends in temporal expression. In addition, differentially expressed genes (DEGs) were identified, and most of the DEGs associated with ecdysone signal transduction, mRNA degradation, protein proteolysis, and autophagy were significantly down-regulated in the transition from molt to intermolt, suggesting that these pathways were activated for the silk gland renewal. These findings provide insights into the molecular mechanisms of silk gland development and silk protein genes transcriptional regulation during the molt to intermolt transition process.
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Affiliation(s)
- Wenbo Hu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Chun Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Chongqing 400716, China
| | - Tingcai Cheng
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Wei Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Niannian Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Chongqing 400716, China.
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22
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Zhou C, Zha X, Shi P, Wei S, Wang H, Zheng R, Xia Q. Multiprotein bridging factor 2 regulates the expression of the fibroin heavy chain gene by interacting with Bmdimmed in the silkworm Bombyx mori. INSECT MOLECULAR BIOLOGY 2016; 25:509-518. [PMID: 27110998 DOI: 10.1111/imb.12239] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Multiprotein bridging factor 2 (MBF2) was first isolated from the posterior silk gland of Bombyx mori. However, its function in B. mori is still unknown. Herein, MBF2 transcripts were detected mainly in the posterior silk gland and Malpighian tubules of B. mori larvae via a quantitative PCR analysis. An analysis of temporal expression patterns showed that the expression pattern of MBF2 was the opposite of that of the fibroin heavy chain (fibH) gene, as its expression was high during the fourth-instar moulting stage, decreased gradually during the fifth-instar feeding stage and disappeared at the end of the fifth-instar phase. Furthermore, bimolecular fluorescent complementation and Far-Western blot assays showed that MBF2 interacted with the basic helix-loop-helix transcription factor Bmdimmed. Dual luciferase reporter assays showed that MBF2 down-regulated the promoter activity of fibH and inhibited the effect of Bmdimmed (Bmdimm) on fibH expression. MBF2 expression was induced in silk glands after treatment with 20-hydroxyecdysone in vivo and in vitro. These findings suggest that MBF2 is a transcriptional repressor that is involved in controlling the regulation of the fibH gene in the posterior silk gland by interacting with Bmdimm.
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Affiliation(s)
- C Zhou
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - X Zha
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - P Shi
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - S Wei
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - H Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - R Zheng
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Q Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
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Nuclear hormone receptor BmFTZ-F1 is involved in regulating the fibroin heavy chain gene in the silkworm, Bombyx mori. Biochim Biophys Acta Gen Subj 2016; 1860:2529-2536. [PMID: 27475001 DOI: 10.1016/j.bbagen.2016.07.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 06/28/2016] [Accepted: 07/25/2016] [Indexed: 11/24/2022]
Abstract
BACKGROUND The synthesis of silk protein is controlled by hormones. The expression of the nuclear hormone Bmftz-f1 in the posterior silk gland (PSG) is induced by 20-hydroxyecdysone in vivo and in vitro. However, whether Bmftz-f1 regulates silk protein expression is unknown. METHODS In our study, western blotting and quantitative polymerase chain reactions were conducted to detect the expression of FTZ-F1 in the PSG. Electrophoretic mobility shift, chromatin immunoprecipitation, far-western blotting, bimolecular fluorescence complementation, and dual luciferase reporter assays were performed to investigate the effect of FTZ-F1 on the fibH promoter. RESULTS (1) The expression of the hormone receptor BmFTZ-F1 was opposite to that of fibH. It was highly expressed in the PSG during the fourth molting stage and the beginning of the fifth instar, and then its expression decreased gradually until it disappeared at the end of the fifth instar and the wandering stage. (2) We identified a FTZ-F1 response element 390bp upstream of the transcription initiation site of the fibH promoter. (3) BmFTZ-F1 interacted with the basic helix-loop-helix transcription factor Bmdimm. (4) BmFTZ-F1 down-regulated fibH promoter activity and counteracted the effect of Bmdimm on fibH expression. CONCLUSIONS Integrating these results, we conclude that BmFTZ-F1 regulates the transcription of fibH by binding to the FTZ-F1 response element in the fibH promoter and counteracts the effect of Bmdimm on fibH expression. GENERAL SIGNIFICANCE These findings provide new insights into the mechanism of regulation of the silk protein gene.
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24
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Takiya S, Tsubota T, Kimoto M. Regulation of Silk Genes by Hox and Homeodomain Proteins in the Terminal Differentiated Silk Gland of the Silkworm Bombyx mori. J Dev Biol 2016; 4:E19. [PMID: 29615585 PMCID: PMC5831788 DOI: 10.3390/jdb4020019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/08/2016] [Accepted: 05/17/2016] [Indexed: 12/15/2022] Open
Abstract
The silk gland of the silkworm Bombyx mori is a long tubular organ that is divided into several subparts along its anteroposterior (AP) axis. As a trait of terminal differentiation of the silk gland, several silk protein genes are expressed with unique regional specificities. Most of the Hox and some of the homeobox genes are also expressed in the differentiated silk gland with regional specificities. The expression patterns of Hox genes in the silk gland roughly correspond to those in embryogenesis showing "colinearity". The central Hox class protein Antennapedia (Antp) directly regulates the expression of several middle silk gland-specific silk genes, whereas the Lin-1/Isl-1/Mec3 (LIM)-homeodomain transcriptional factor Arrowhead (Awh) regulates the expression of posterior silk gland-specific genes for silk fiber proteins. We summarize our results and discuss the usefulness of the silk gland of Bombyx mori for analyzing the function of Hox genes. Further analyses of the regulatory mechanisms underlying the region-specific expression of silk genes will provide novel insights into the molecular bases for target-gene selection and regulation by Hox and homeodomain proteins.
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Affiliation(s)
- Shigeharu Takiya
- Shigeharu Takiya, Division of Biological Sciences and Center for Genome Dynamics, Faculty of Science, Hokkaido University, North 10, West 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
- Graduate School of Life Science, Hokkaido University, North 10, West 8, Kita-ku, Sapporo 060-0810, Japan.
| | - Takuya Tsubota
- Transgenic Silkworm Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 1-2 Owashi, Tsukuba, Ibaraki 305-8634, Japan.
| | - Mai Kimoto
- Graduate School of Life Science, Hokkaido University, North 10, West 8, Kita-ku, Sapporo 060-0810, Japan.
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25
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Li J, Qin S, Yu H, Zhang J, Liu N, Yu Y, Hou C, Li M. Comparative Transcriptome Analysis Reveals Different Silk Yields of Two Silkworm Strains. PLoS One 2016; 11:e0155329. [PMID: 27159277 PMCID: PMC4861282 DOI: 10.1371/journal.pone.0155329] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 04/27/2016] [Indexed: 12/17/2022] Open
Abstract
Cocoon and silk yields are the most important characteristics of sericulture. However, few studies have examined the genes that modulate these features. Further studies of these genes will be useful for improving the products of sericulture. JingSong (JS) and Lan10 (L10) are two strains having significantly different cocoon and silk yields. In the current study, RNA-Seq and quantitative polymerase chain reaction (qPCR) were performed on both strains in order to determine divergence of the silk gland, which controls silk biosynthesis in silkworms. Compared with L10, JS had 1375 differentially expressed genes (DEGs; 738 up-regulated genes and 673 down-regulated genes). Nine enriched gene ontology (GO) terms were identified by GO enrichment analysis based on these DEGs. KEGG enrichment analysis results showed that the DEGs were enriched in three pathways, which were mainly associated with the processing and biosynthesis of proteins. The representative genes in the enrichment pathways and ten significant DEGs were further verified by qPCR, the results of which were consistent with the RNA-Seq data. Our study has revealed differences in silk glands between the two silkworm strains and provides a perspective for understanding the molecular mechanisms determining silk yield.
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Affiliation(s)
- Juan Li
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang Jiangsu 212018, China
| | - Sheng Qin
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang Jiangsu 212018, China
- The Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang Jiangsu 212018, China
| | - Huanjun Yu
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang Jiangsu 212018, China
| | - Jing Zhang
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang Jiangsu 212018, China
| | - Na Liu
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang Jiangsu 212018, China
| | - Ye Yu
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang Jiangsu 212018, China
| | - Chengxiang Hou
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang Jiangsu 212018, China
- The Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang Jiangsu 212018, China
| | - Muwang Li
- School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang Jiangsu 212018, China
- The Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang Jiangsu 212018, China
- * E-mail:
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26
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Yu LY, Cheng W, Zhou K, Li WF, Yu HM, Gao X, Shen X, Wu Q, Chen Y, Zhou CZ. Structures of an all-α protein running along the DNA major groove. Nucleic Acids Res 2016; 44:3936-45. [PMID: 26939889 PMCID: PMC4856987 DOI: 10.1093/nar/gkw133] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 02/23/2016] [Indexed: 02/06/2023] Open
Abstract
Despite over 3300 protein–DNA complex structures have been reported in the past decades, there remain some unknown recognition patterns between protein and target DNA. The silkgland-specific transcription factor FMBP-1 from the silkworm Bombyx mori contains a unique DNA-binding domain of four tandem STPRs, namely the score and three amino acid peptide repeats. Here we report three structures of this STPR domain (termed BmSTPR) in complex with DNA of various lengths. In the presence of target DNA, BmSTPR adopts a zig-zag structure of three or four tandem α-helices that run along the major groove of DNA. Structural analyses combined with binding assays indicate BmSTPR prefers the AT-rich sequences, with each α-helix covering a DNA sequence of 4 bp. The successive AT-rich DNAs adopt a wider major groove, which is in complementary in shape and size to the tandem α-helices of BmSTPR. Substitutions of DNA sequences and affinity comparison further prove that BmSTPR recognizes the major groove mainly via shape readout. Multiple-sequence alignment suggests this unique DNA-binding pattern should be highly conserved for the STPR domain containing proteins which are widespread in animals. Together, our findings provide structural insights into the specific interactions between a novel DNA-binding protein and a unique deformed B-DNA.
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Affiliation(s)
- Li-Yan Yu
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Wang Cheng
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Kang Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Wei-Fang Li
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Hong-Mei Yu
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Xinlei Gao
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Xudong Shen
- School of Information Science and Technology, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Qingfa Wu
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Yuxing Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Cong-Zhao Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
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Biochemical characterization and functional analysis of the POU transcription factor POU-M2 of Bombyx mori. Int J Biol Macromol 2016; 86:701-8. [PMID: 26854886 DOI: 10.1016/j.ijbiomac.2016.02.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 02/02/2016] [Accepted: 02/03/2016] [Indexed: 11/21/2022]
Abstract
POU-M2 is a homeodomain transcription factor which plays important roles in the development and silk synthesis of Bombyx mori. In this study, we expressed, purified and characterized POU-M2 and studied its transcription regulation on fibroin heavy chain gene of Bombyx mori. Gel filtration showed POU-M2 existed as a dimer in solution. Far-UV circular dichroism spectra indicated POU-M2 had a well-defined α-helix structure and the α-helix content was about 26.4%. The thermal unfolding transition of POU-M2 was a cooperative process. Tm, ΔH and ΔS were 45.15 ± 0.2 °C, 138.4 ± 0.5 KJ/mol and 0.4349 ± 0.04 KJ/(mol·K), respectively. Western blotting analysis indicated the expression level of POU-M2 increased slightly from day 3 to day 7 of the fifth instar larvae in the posterior silk gland. POU-M2 was positioned in the nucleus of cells. The luciferase reporter assay demonstrated POU-M2 could stimulate the promoter activity of fibroin heavy chain gene, and the activation effect was dependent on the amount of POU-M2. Our study suggested POU-M2 may be involved in the transcriptional regulation of fibroin heavy chain gene. These findings expand toward a better understanding of the structure of POU-M2 and its function in silk synthesis of Bombyx mori.
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Wang X, Tang S, Song F, Chen C, Guo X, Shen X. Bmo-miR-2758 Targets BmFMBP-1 (Lepidoptera: Bombycidae) and Suppresses Its Expression in BmN Cells. JOURNAL OF INSECT SCIENCE (ONLINE) 2016; 16:iew009. [PMID: 27001963 PMCID: PMC4801057 DOI: 10.1093/jisesa/iew009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 01/28/2016] [Indexed: 05/08/2023]
Abstract
MicroRNAs (miRNAs) are an abundant family of endogenous noncoding small RNA molecules. They play crucial roles on regulation of life processes both in plants and animals. Fibroin modulator binding protein-1 (FMBP-1) is a silk gland transcription factor of Bombyx mori, which is considered as a trans-activator of fibroin genes. And bioinformatics prediction showed that at the 3' untranslated region (3' UTR) of BmFMBP-1 there were binding sites for three bmo-miRNAs, bmo-miR-2b*, bmo-miR-305, and bmo-miR-2758, separately. In order to validate whether these bmo-miRNAs involved in the regulation of BmFMBP-1 expression, the expression levels of three bmo-miRNAs and BmFMBP-1 in the middle silk gland (MSG) and posterior silk gland (PSG) during the fourth- and fifth-larval stages of B. mori were measured by semi-quantitative reverse transcription polymerase chain reaction. The results revealed that the expression level of bmo-miR-2758 was the highest in the three, and it expressed higher in the PSG than in the MSG with a similar expression pattern as BmFMBP-1, implying that bmo-miR-2758 may involved in regulation of BmFMBP-1. To validate the regulation function of bmo-miR-2758 on BmFMBP-1, recombinant plasmids pcDNA3 [ie1-egfp-pri-bmo-miR-2758-SV40] and pGL3 [A3-luc-FMBP-1 3' UTR-SV40] were constructed and co-transfected in BmN cells. The dual-luciferase reporter assay system was used for assay of transient expression. The results showed that the expression of the luciferase reporter was significantly decreased when pGL3 [A3-luc-FMBP-1 3' UTR-SV40] co-transfected with pcDNA3 [ie1-egfp-pri-bmo-miR-2758-SV40] (P < .01). Furthermore, when the artificial antisense RNA of bmo-miR-2758 (inhibitor) was added to the above co-transfection, the expression of the luciferase reporter was recovered significantly (P < 0.01). These results suggest that bmo-miR-2758 represses the expression of BmFMBP-1 in vitro.
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Affiliation(s)
- Xin Wang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, China
| | - Shunming Tang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, China
| | - Fei Song
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Chen Chen
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Xijie Guo
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, China
| | - Xingjia Shen
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China; Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, China
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Wang H, Wang L, Wang Y, Tao H, Yin W, SiMa Y, Wang Y, Xu S. High yield exogenous protein HPL production in the Bombyx mori silk gland provides novel insight into recombinant expression systems. Sci Rep 2015; 5:13839. [PMID: 26370318 PMCID: PMC4570194 DOI: 10.1038/srep13839] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 08/06/2015] [Indexed: 01/24/2023] Open
Abstract
The silk gland of Bombyx mori (BmSG) has gained significant attention by dint of superior synthesis and secretion of proteins. However, the application of BmSG bioreactor is still a controversial issue because of low yields of recombinant proteins. Here, a 3057 bp full-length coding sequence of Hpl was designed and transformed into the silkworm genome, and then the mutant (Hpl/Hpl) with specific expression of Hpl in posterior BmSG (BmPSG) was obtained. In the mutants, the transcription level of Fib-L and P25, and corresponding encoding proteins, did not decrease. However, the mRNA level of Fib-H was reduced by 71.1%, and Fib-H protein in the secreted fibroin was decreased from 91.86% to 71.01%. The mRNA level of Hpl was 0.73% and 0.74% of Fib-H and Fib-L, respectively, while HPL protein accounted for 18.85% of fibroin and 15.46% of the total amount of secreted silk protein. The exogenous protein was therefore very efficiently translated and secreted. Further analysis of differentially expressed gene (DEG) was carried out in the BmPSG cells and 891 DEGs were detected, of which 208 genes were related to protein metabolism. Reduced expression of endogenous silk proteins in the BmPSG could effectively improve the production efficiency of recombinant exogenous proteins.
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Affiliation(s)
- Huan Wang
- School of Biology and Basic Medical Sciences, Medical College, Soochow University, Suzhou 215123, China
| | - Lu Wang
- School of Biology and Basic Medical Sciences, Medical College, Soochow University, Suzhou 215123, China
| | - Yulong Wang
- School of Biology and Basic Medical Sciences, Medical College, Soochow University, Suzhou 215123, China
| | - Hui Tao
- School of Biology and Basic Medical Sciences, Medical College, Soochow University, Suzhou 215123, China
| | - Weimin Yin
- School of Biology and Basic Medical Sciences, Medical College, Soochow University, Suzhou 215123, China
| | - Yanghu SiMa
- School of Biology and Basic Medical Sciences, Medical College, Soochow University, Suzhou 215123, China
| | - Yujun Wang
- R&D Division, Okamoto Corporation, Nara 635-8550, Japan
| | - Shiqing Xu
- School of Biology and Basic Medical Sciences, Medical College, Soochow University, Suzhou 215123, China.,National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123, China
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30
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Zhao XM, Liu C, Jiang LJ, Li QY, Zhou MT, Cheng TC, Mita K, Xia QY. A juvenile hormone transcription factor Bmdimm-fibroin H chain pathway is involved in the synthesis of silk protein in silkworm, Bombyx mori. J Biol Chem 2015; 290:972-86. [PMID: 25371208 PMCID: PMC4294524 DOI: 10.1074/jbc.m114.606921] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 11/03/2014] [Indexed: 01/16/2023] Open
Abstract
The genes responsible for silk biosynthesis are switched on and off at particular times in the silk glands of Bombyx mori. This switch appears to be under the control of endogenous and exogenous hormones. However, the molecular mechanisms by which silk protein synthesis is regulated by the juvenile hormone (JH) are largely unknown. Here, we report a basic helix-loop-helix transcription factor, Bmdimm, its silk gland-specific expression, and its direct involvement in the regulation of fibroin H-chain (fib-H) by binding to an E-box (CAAATG) element of the fib-H gene promoter. Far-Western blots, enzyme-linked immunosorbent assays, and co-immunoprecipitation assays revealed that Bmdimm protein interacted with another basic helix-loop-helix transcription factor, Bmsage. Immunostaining revealed that Bmdimm and Bmsage proteins are co-localized in nuclei. Bmdimm expression was induced in larval silk glands in vivo, in silk glands cultured in vitro, and in B. mori cell lines after treatment with a JH analog. The JH effect on Bmdimm was mediated by the JH-Met-Kr-h1 signaling pathway, and Bmdimm expression did not respond to JH by RNA interference with double-stranded BmKr-h1 RNA. These data suggest that the JH regulatory pathway, the transcription factor Bmdimm, and the targeted fib-H gene contribute to the synthesis of fibroin H-chain protein in B. mori.
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Affiliation(s)
- Xiao-Ming Zhao
- From the State Key Laboratory of Silkworm Genome Biology and Key Sericultural Laboratory of the Ministry of Agriculture, College of Bio-Technology, Southwest University, Chongqing 400716 and the Research Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Chun Liu
- From the State Key Laboratory of Silkworm Genome Biology and Key Sericultural Laboratory of the Ministry of Agriculture, College of Bio-Technology, Southwest University, Chongqing 400716 and
| | - Li-Jun Jiang
- From the State Key Laboratory of Silkworm Genome Biology and Key Sericultural Laboratory of the Ministry of Agriculture, College of Bio-Technology, Southwest University, Chongqing 400716 and
| | - Qiong-Yan Li
- From the State Key Laboratory of Silkworm Genome Biology and Key Sericultural Laboratory of the Ministry of Agriculture, College of Bio-Technology, Southwest University, Chongqing 400716 and
| | - Meng-Ting Zhou
- From the State Key Laboratory of Silkworm Genome Biology and Key Sericultural Laboratory of the Ministry of Agriculture, College of Bio-Technology, Southwest University, Chongqing 400716 and
| | - Ting-Cai Cheng
- From the State Key Laboratory of Silkworm Genome Biology and Key Sericultural Laboratory of the Ministry of Agriculture, College of Bio-Technology, Southwest University, Chongqing 400716 and
| | - Kazuei Mita
- From the State Key Laboratory of Silkworm Genome Biology and
| | - Qing-You Xia
- From the State Key Laboratory of Silkworm Genome Biology and Key Sericultural Laboratory of the Ministry of Agriculture, College of Bio-Technology, Southwest University, Chongqing 400716 and
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31
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Li DD, Liu ZC, Huang L, Jiang QL, Zhang K, Qiao HL, Jiao ZJ, Yao LG, Liu RY, Kan YC. The expression analysis of silk gland-enriched intermediate-size non-coding RNAs in silkworm Bombyx mori. INSECT SCIENCE 2014; 21:429-438. [PMID: 24124013 DOI: 10.1111/1744-7917.12063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/22/2013] [Indexed: 06/02/2023]
Abstract
Small non-protein coding RNAs (ncRNAs) play important roles in development, stress response and other cellular processes. Silkworm is an important model for studies on insect genetics and control of Lepidopterous pests. We have previously identified 189 novel intermediate-size ncRNAs in silkworm Bombyx mori, including 40 ncRNAs that showed altered expression in different developmental stages. Here we characterized the functions of these 40 ncRNAs by measuring their expressions in six tissues of the fifth instar larvae using Northern blot and real-time polymerase chain reaction assays. We identified nine ncRNAs (four small nucleolar RNAs and five unclassified ncRNAs) that were enriched in silk gland, including four ncRNAs that showed silk gland-specific expression. We further showed that three of nine silk gland-enriched ncRNAs were predominantly expressed in the anterior silk gland, whereas another three ncRNAs were highly accumulated in the posterior silk gland, suggesting that they may play different roles in fibroin synthesis. Furthermore, an unclassified ncRNA, Bm-152, exhibited converse expression pattern with its antisense host gene gartenzwerg in diverse tissues, and might regulate the expression of gartenzwerg through RNA-protein complex. In addition, two silk gland-enriched ncRNAs Bm-102 and Bm-159 can be found in histone modification complex, which indicated that they might play roles through epigenetic modifications. Taken together, we provided the first expression and preliminary functional analysis of silk gland-enriched ncRNAs, which will help understand the molecular mechanism of silk gland-development and fibroin synthesis.
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Affiliation(s)
- Dan-Dan Li
- China-UK-NYNU-RRes Joint Libratory of Insect Biology, Nanyang Normal University, Nanyang, Henan, China
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Kimoto M, Tsubota T, Uchino K, Sezutsu H, Takiya S. Hox transcription factor Antp regulates sericin-1 gene expression in the terminal differentiated silk gland of Bombyx mori. Dev Biol 2013; 386:64-71. [PMID: 24333180 DOI: 10.1016/j.ydbio.2013.12.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 11/07/2013] [Accepted: 12/03/2013] [Indexed: 11/18/2022]
Abstract
Hox genes are well-known master regulators in developmental morphogenesis along the anteroposterior axis of animals. However, the molecular mechanisms by which Hox proteins regulate their target genes and determine cell fates are not fully understood. The silk gland of Bombyx mori is a tubular tissue divided into several subparts along the anteroposterior axis, and the silk genes are expressed with specific patterns. The sericin-1 gene (ser1) is expressed in the middle silk gland (MSG) with sublocal specificity. Here we show that the Hox protein Antp is a component of the middle silk gland-specific complex, MIC (MSG-intermolt-specific complex), binds to the essential promoter element of ser1, and activates its expression. Ectopic expression of Antp in transgenic silkworms induced the expression of ser1 in the posterior silk gland (PSG), but not in the anterior part of MSG (MSG-A). Correspondingly, a MIC-like complex was formed by the addition of recombinant Antp in extracts from PSG with its cofactors Exd and Hth, but not in extracts from MSG-A. Splicing patterns of ser1 mRNA induced by the ectopic expression of Antp in PSG were almost the same as those in MSG at the fifth instar and altered depending on the induction timing of Antp. Other Hox genes were expressed with sublocal specificity in the silk gland. The Bombyx silk gland might provide a useful system for understanding how Hox proteins select and regulate their target genes.
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Affiliation(s)
- Mai Kimoto
- Graduate School of Life Science, Hokkaido University, Japan
| | - Takuya Tsubota
- Transgenic Silkworm Research Unit, National Institute of Agrobiological Sciences, Owashi 1-2, Tsukuba, Ibaraki 305-8634, Japan
| | - Keiro Uchino
- Transgenic Silkworm Research Unit, National Institute of Agrobiological Sciences, Owashi 1-2, Tsukuba, Ibaraki 305-8634, Japan
| | - Hideki Sezutsu
- Transgenic Silkworm Research Unit, National Institute of Agrobiological Sciences, Owashi 1-2, Tsukuba, Ibaraki 305-8634, Japan
| | - Shigeharu Takiya
- Graduate School of Life Science, Hokkaido University, Japan; Division of Biological Sciences and Center for Genome Dynamics, Faculty of Science, Hokkaido University, North 10, West 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
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33
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Inhibition of the binding of MSG-intermolt-specific complex, MIC, to the sericin-1 gene promoter and sericin-1 gene expression by POU-M1/SGF-3. Dev Genes Evol 2012; 222:351-9. [DOI: 10.1007/s00427-012-0418-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 09/28/2012] [Indexed: 10/27/2022]
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Takiya S, Inoue H, Kimoto M. Novel enhancer and promoter elements indispensable for the tissue-specific expression of the sericin-1 gene of the silkworm Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2011; 41:592-601. [PMID: 21496486 DOI: 10.1016/j.ibmb.2011.03.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 03/21/2011] [Accepted: 03/29/2011] [Indexed: 05/30/2023]
Abstract
Sericins are glue proteins produced specifically in the middle silk gland (MSG) of the silkworm Bombyx mori, while the silk fiber protein, fibroin, is produced in the posterior silk gland (PSG). These silk proteins are expected to be useful biomaterials in medical technology as well as biotechnology. In this study, we analyzed promoter elements of the sericin-1 gene (ser1) in vivo by introducing reporter constructs into silk glands via gene gun technology. The region from -1602 to +47 was sufficient to induce MSG-specific expression. The 5' deletion mutants showed a three-step decrease in promoter activity with the key sequences located between -1362 and -1250, -201 and -116, and -115 and -37. We detected a tissue- and stage-specific factor complex (MSG-intermolt-specific complex: MIC) bound to the sequence elements around the -1350, -320, -180, and -70 regions. A mutation in the -70 region, which inhibits MIC-binding, diminished almost all promoter activity, while another mutation that did not inhibit MIC-binding showed no effect on promoter activity. The results suggest that the binding of MIC to the above elements is intrinsic for the spatiotemporal specificity of ser1 in vivo.
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Affiliation(s)
- Shigeharu Takiya
- Division of Biological Sciences and Center for Genome Dynamics, Faculty of Science, Hokkaido University, North 10, West 8, Kita-ku, Sapporo 060-0810, Japan.
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35
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Li JY, Yang HJ, Lan TY, Wei H, Zhang HR, Chen M, Fan W, Ma YY, Zhong BX. Expression profiling and regulation of genes related to silkworm posterior silk gland development and fibroin synthesis. J Proteome Res 2011; 10:3551-64. [PMID: 21657221 DOI: 10.1021/pr200196x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The posterior silk gland (PSG) is the most important suborgan responsible for the synthesis and secretion of silk core fibroin proteins in silkworm. Here, we performed genome-scale expression profiling analysis of silkworm PSG at the fourth molting (M4) and at day 1 (V1), day 3 (V3), day 5 (V5), and wandering stage (W) of the fifth instar by microarray analysis with 22 987 probes. We found that the five genes of silk proteins secreted from PSG including fibroin heavy (H) and light (L) chains, P25, seroin 1, and seroin 2 basically showed obvious up-regulation at V3 which lasted to V5, while slight down-regulation at W. The expression of translation-related genes including ribosomal proteins and translation initiation factors generally remained stable from M4 to V5, whereas it showed clear down-regulation at W. Clustering analysis of the 643 significantly differentially expressed transcripts revealed that 43 of the important genes including seroin 1 and sugar transporter protein had co-expression patterns which were consistent with the rate changes of fibroin synthesis and PSG growth. Pathway analysis disclosed that the genes in different clusters might have co-regulations and direct interactions. These genes were supposed to be involved in the fibroin synthesis and secretion. The differential expression of several hormone-related genes also suggested their functions on the regulation of PSG development and fibroin synthesis. 2D gel-based proteomics and phosphoproteomics profiling revealed that the phosphorylated proteins accounted for no more than one-sixth of the total proteins at each stage, which was much lower than the level in normal eukaryotic cells. Changes in the phosphorylation status and levels of several proteins such as actin-depolymerizing factor 1 and enolase might be deeply involved in fibroin secretion and tissue development. Shotgun proteomic profiling combined with label-free quantification analysis on the PSG at V3, V5, and W revealed that many small heat shock proteins (sHSP) were specially expressed at W, which was substantially consistent with the results from 2-DE analysis, and implied the close correlations of sHSP with the physiological states of PSG at W. A majority of significantly up-regulated proteins at V5 were related to ribosome pathway, which was different from the microarray results, implying that the translation-level regulation of ribosomal proteins might be critical for fibroin synthesis. In contrast, the ubiquitin-proteasome pathway related proteins appeared obviously up-regulated at W, suggesting that the programmed cell death process of PSG cells might be started before cocooning.
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Affiliation(s)
- Jian-ying Li
- College of Animal Sciences, Zhejiang University, Hangzhou 310029, PR China
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36
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Natural protective glue protein, sericin bioengineered by silkworms: Potential for biomedical and biotechnological applications. Prog Polym Sci 2008. [DOI: 10.1016/j.progpolymsci.2008.08.002] [Citation(s) in RCA: 263] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Shimizu K, Ogawa S, Hino R, Adachi T, Tomita M, Yoshizato K. Structure and function of 5'-flanking regions of Bombyx mori fibroin heavy chain gene: identification of a novel transcription enhancing element with a homeodomain protein-binding motif. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2007; 37:713-25. [PMID: 17550827 DOI: 10.1016/j.ibmb.2007.03.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 03/27/2007] [Accepted: 03/31/2007] [Indexed: 05/15/2023]
Abstract
We studied the promoter activity of a 5'-flanking region from -5000 to +24 (-5000/+24) in Bombyx mori fibroin heavy chain gene (fibH), fibH(-5000/+24). A luciferase reporter vector carrying fibH(-5000/+24) was bombarded to isolated posterior silk glands (PSGs). The PSGs showed a high luciferase activity when transplanted to larvae, indicating its potent promoter activity. Deletion experiments showed the requirement of fibH(-5000/-3844) and fibH(-2211/-542) for the promoter activity. These two regions and fibH(-541/+24) that contained the basal promoter were tandem fused to yield fibH(-5000/-3844:-2211/-542:-541/+24), which was found to retain 88% of the activity of fibH(-5000/+24). Germline transgenic silkworms bearing fibH(-5000/-3844:-2211/-542:-541/+24) as a promoter and enhanced green fluorescent protein (EGFP) gene as a reporter efficiently secreted EGFP in cocoons. The promoter activity of fibH(-2211/-542) was further investigated, because this contained a DNase I-hypersensitive site. The transient expression assay demonstrated that the activity of fibH(-2211/-542) required fibH(-1659/-1590), which contained the homeodomain protein-binding motif. Mutation experiments suggested a critical role of the motif for the promoter activity. Electrophoretic mobility shift assay (EMSA) demonstrated that a nuclear protein of PSGs bound to the motif. We propose fibH(-1659/-1590) as a novel transcription enhancer that plays a key role for the expression by recruiting a homeodomain protein.
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Affiliation(s)
- Katsuhiko Shimizu
- Yoshizato Project, Cooperative Link of Unique Science and Technology for Economy Revitalization, Hiroshima Prefectural Institute of Industrial Science and Technology, 3-10-32 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan
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38
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Takiya S, Ishikawa T, Ohtsuka K, Nishita Y, Suzuki Y. Fibroin-modulator-binding protein-1 (FMBP-1) contains a novel DNA-binding domain, repeats of the score and three amino acid peptide (STP), conserved from Caenorhabditis elegans to humans. Nucleic Acids Res 2005; 33:786-95. [PMID: 15687387 PMCID: PMC548367 DOI: 10.1093/nar/gki228] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Revised: 01/18/2004] [Accepted: 01/18/2004] [Indexed: 11/13/2022] Open
Abstract
The predicted transcriptional regulatory factor for the fibroin gene of the silkworm Bombyx mori, fibroin-modulator-binding protein-1 (FMBP-1), was purified by sequential DNA affinity column chromatography, and cDNA clones corresponding to FMBP-1 were isolated from a library. The N-terminal half of FMBP-1 has a weak similarity to the DNA-binding domain of several transcriptional regulatory factors in higher plants. The C-terminal half contains four tandem repeats of a novel 23 amino acid motif, which we named the score and three amino acid peptide (STP). Other genes containing STP repeats were found in Drosophila, Caenorhabditis elegans, mouse and human. Mutational analysis of FMBP-1 showed that the STP repeats form a novel DNA-binding domain. Sequences flanking STP repeats modulated DNA-binding activity. The FMBP-1 gene was expressed during the fourth to fifth instar. FMBP-1 activity appeared to be regulated at the transcriptional level and by the post-transcriptional modification.
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Affiliation(s)
- Shigeharu Takiya
- Center for Advanced Science and Technology and Hokkaido UniversityNorth 10, West 8, Kita-ku, Sapporo 060-0810, Japan
- Graduate School of Environmental Earth Science, Hokkaido UniversityNorth 10, West 8, Kita-ku, Sapporo 060-0810, Japan
| | - Tetsurou Ishikawa
- Graduate School of Environmental Earth Science, Hokkaido UniversityNorth 10, West 8, Kita-ku, Sapporo 060-0810, Japan
| | - Katsuya Ohtsuka
- Graduate School of Environmental Earth Science, Hokkaido UniversityNorth 10, West 8, Kita-ku, Sapporo 060-0810, Japan
| | - Yoshinori Nishita
- Center for Advanced Science and Technology and Hokkaido UniversityNorth 10, West 8, Kita-ku, Sapporo 060-0810, Japan
| | - Yoshiaki Suzuki
- National Institute for Basic BiologyNishigo-naka 38, Okazaki 444-8585, Japan
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39
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Miao YG, Nair KS. Exogenous prostaglandin F2α as a mediator in the regulation of silkworm growth and silk gland genome. Prostaglandins Other Lipid Mediat 2003; 72:147-54. [PMID: 14674626 DOI: 10.1016/s1098-8823(03)00072-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Prostaglandins are locally acting hormones that have remarkable variety of physiological functions. They are rapidly synthesized in several types of vertebrate cells as oxygenated metabolites of arachidonic acid in response to various stimuli. In many insect species they are biosynthesized in fat body and hemocytes mainly in response to bacterial infections. In the present study, we administered synthetic analog of prostaglandin F2alpha, the most prominent of the prostaglandins to the 48 h old fifth instar silkworm, Bombyx mori L. at a single dose of 4 microg per larva to study its effects on the larval growth pattern and silk synthesis. The possible role of PGF2alpha at altering the quantum of silk synthesis by controlling the silk gene expression was also studied. The genomic DNA was isolated from the posterior silk gland on Days 5 and 7 of the fifth instar from the prostaglandin treated and the control larvae and were random amplified with arbitrary primers. The result presented notable variation in the amplified product suggesting the participation of PGF2alpha in the silk biosynthesis controlling the silk gene expression. The feeding period of treated larvae was unaffected while the cocoon characters exhibited considerable improvement. The filament traits also were improved notably in the treated larvae. The participation of PGF2alpha analog in the silk biosynthetic process with its physiological and molecular implications are discussed.
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Affiliation(s)
- Yun-Gen Miao
- Department of Sericulture, College of Animal Sciences, Zhejiang University, Hangzhou-310029, PR China.
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40
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Datta A, Ghosh AK, Kundu SC. Differential expression of the fibroin gene in developmental stages of silkworm, Antheraea mylitta (Saturniidae). Comp Biochem Physiol B Biochem Mol Biol 2001; 129:197-204. [PMID: 11337263 DOI: 10.1016/s1096-4959(01)00377-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Fibroin gene expression during the larval developmental stages of the Saturniid silkworm, Antheraea mylitta, was analyzed. Northern blot analysis of larval silk gland total RNA using the fibroin gene as a probe showed that fibroin is expressed in the intermoult stages and repressed during the moulting stages. Abundance of fibroin transcripts gradually increased from the third to fifth intermoult stage, reaching a peak in the fifth intermoult. Transcripts declined during the early spinning stage. Western blot analysis of fibroin protein production with anti-fibroin antibody confirmed the differential fibroin expression, in accordance with fibroin mRNA synthesis. Dot blot hybridization of genomic DNA isolated from each larval developmental stage with the labelled fibroin gene showed that at the genomic level, the relative concentration of the fibroin gene was constant throughout the developmental stages. Our data confirm that fibroin gene expression in A. mylitta, like in B. mori, is transcriptionally controlled and shows differential temporal variations.
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Affiliation(s)
- A Datta
- Department of Biotechnology, Indian Institute of Technology, 721302, Kharagpur, India
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41
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Matsunami K, Kokubo H, Ohno K, Suzuki Y. Expression pattern analysis of SGF-3/POU-M1 in relation to sericin-1 gene expression in the silk gland. Dev Growth Differ 1998; 40:591-7. [PMID: 9865969 DOI: 10.1046/j.1440-169x.1998.t01-4-00003.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Embryonic and larval expression patterns of the sericin-1 gene and its presumed transcription factor, SGF-3/POU-M1, in the silk gland were analyzed by in situ hybridization and immunohistochemistry. The sericin-1 transcripts were first detected at embryonic stage 26 in an increasing gradient pattern in the middle and posterior part of the middle silk gland (MSG), while at the same stage the SGF-3/POU-M1 was already present in the entire anterior silk gland (ASG) and in the MSG but with a decreasing gradient pattern. The latter expression pattern was consistently maintained through all larval stages, while the sericin-1 expression was detected during the feeding stages but disappeared at the molting stages. These observations suggest that, although the SGF-3/POU-M1 was proposed to be a positive transcription factor for the sericin-1 gene, the protein might function in a negative manner on sericin-1 gene transcription. Alternatively, it is also possible that the sericin-1 gene might require another unidentified factor or mediator for in vivo transcription.
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Affiliation(s)
- K Matsunami
- Graduate University for Advanced Studies, Okazaki, Japan
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42
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Takiya S, Kokubo H, Suzuki Y. Transcriptional regulatory elements in the upstream and intron of the fibroin gene bind three specific factors POU-M1, Bm Fkh and FMBP-1. Biochem J 1997; 321 ( Pt 3):645-53. [PMID: 9032449 PMCID: PMC1218118 DOI: 10.1042/bj3210645] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The transcriptional modulator in the fibroin gene intron is composed of multiple octamer-like AT-rich elements, to which several specific DNA-binding proteins named fibroin-modulator-binding proteins (FMBPs) bind. Three major FMBPs in the silk gland were characterized. Two of them (FMBP-2 and -3) were identified as a Fork head homologue (Bm Fkh) and a POU-domain protein (POU-M1) respectively. These factors were expressed in the silk gland with distinct temporal- and spatial-specificities during late larval development as well as during embryogenesis, and did not correlate directly with fibroin gene expression. The other (FMBP-1) appeared to correlate with the expression of the fibroin gene for temporal- and spatial-specificity. These FMBPs also bind to the elements in the upstream modulator. Transcriptional enhancement by both modulators was inhibited by binding competition for these factors with oligonucleotides. These results suggest that expression of the fibroin gene is controlled by co-ordination of these factors with distinct specificities during silk-gland development.
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Affiliation(s)
- S Takiya
- National Institute for Basic Biology and Graduate University for Advanced Studies, Myodaiji, Okazaki, Japan
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Kamimura M, Tomita S, Fujiwara H. Molecular cloning of an ecdysone receptor (B1 isoform) homologue from the silkworm, Bombyx mori, and its mRNA expression during wing disc development. Comp Biochem Physiol B Biochem Mol Biol 1996; 113:341-7. [PMID: 8653587 DOI: 10.1016/0305-0491(95)02032-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We reported the isolation and sequence of a clone encoding a putative ecdysone receptor B1 isoform of the silkworm, Bombyx mori. The predicted open reading frame encoded 543 amino acids, with 51%, 95% and 71% identities with the Drosophila melanogaster ecdysone receptor B1 isoform in the N terminal A/B region, DNA binding domain (C region) and ligand binding domain (E region), respectively. A single 6.2 kb message for the EcR gene was abundant in wing discs and fat bodies at the onset of metamorphosis. At the same stage, however, no or a tiny amount of mRNA was shown in posterior or middle silk glands, respectively. During the final instar, the mRNA expression in wing discs was maximal on the day of wandering. These data suggest the transcription of the Bombyx EcR gene is regulated in tissue-specific and stage-specific manner during metamorphosis.
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Affiliation(s)
- M Kamimura
- National Institute of Sericultural and Entomological Science, Tsukuba Ibaraki, Japan
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44
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Developmental regulation of silk protein P25 in the silkwormBombyx mori. J Biosci 1995. [DOI: 10.1007/bf02703269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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45
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Abstract
At least three silk genes are specifically expressed in the posterior, and five other genes in middle, silk glands. The products of genes active in PSG include fibroin, L-chain fibroin and P25 protein. PSG genes as well as the Ser-1 gene, differing in structure, exhibit a striking degree of homology of their 5' flanking sequences. This suggests the presence of common regulatory mechanisms. The expression of silk protein genes is probably controlled by tissue-specific and general transcriptional factors. Hormones seem to participate in the regulation of expression of silk protein genes.
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Affiliation(s)
- K Grzelak
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw
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46
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Takiya S, Suzuki Y. Role of the Core Promoter for the Preferential Transcription of Fibroin Gene in the Posterior Silk Gland Extract. (transcription/core promoter/fibroin gene/initiator/DNase I footprint). Dev Growth Differ 1993. [DOI: 10.1111/j.1440-169x.1993.00311.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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47
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P25 gene regulation in Bombyx mori silk gland: two promoter-binding factors have distinct tissue and developmental specificities. Mol Cell Biol 1992. [PMID: 1448104 DOI: 10.1128/mcb.12.12.5768] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The gene encoding the silk protein P25 is expressed in the posterior silk gland of Bombyx mori with strict territorial and developmental specificities. The cis-acting regulatory elements previously located within the 441-bp 5' proximal sequence of the gene were examined for protein-binding capacities. We identified two factors, BMFA and SGFB, that lead to prominent band shifts and the target sites for which are included in a region homologous to the fibroin gene enhancer sequence. Analysis of the tissue-specific incidence of both factors showed that BMFA is ubiquitous, whereas SGFB is restricted to the silk gland cells. However, SGFB was found in both posterior and middle silk gland cells and therefore likely directs organ-specific, but not territory-specific, expression. Developmental studies throughout the fourth larval molt, at which the P25 gene status changes from derepressed to repressed, revealed that BMFA is reversibly modified at the transition from intermolt to molt. Indeed, the preexisting BMFA is replaced by a structurally related factor, BMFA', during the 2 h following head capsule apolysis. The exact temporal coincidence of this conversion with the onset of gene repression suggests that BMFA' is involved in transcription inactivation and likely results from a transduction process initiated by the hormonal change at molting.
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48
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Durand B, Drevet J, Couble P. P25 gene regulation in Bombyx mori silk gland: two promoter-binding factors have distinct tissue and developmental specificities. Mol Cell Biol 1992; 12:5768-77. [PMID: 1448104 PMCID: PMC360516 DOI: 10.1128/mcb.12.12.5768-5777.1992] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The gene encoding the silk protein P25 is expressed in the posterior silk gland of Bombyx mori with strict territorial and developmental specificities. The cis-acting regulatory elements previously located within the 441-bp 5' proximal sequence of the gene were examined for protein-binding capacities. We identified two factors, BMFA and SGFB, that lead to prominent band shifts and the target sites for which are included in a region homologous to the fibroin gene enhancer sequence. Analysis of the tissue-specific incidence of both factors showed that BMFA is ubiquitous, whereas SGFB is restricted to the silk gland cells. However, SGFB was found in both posterior and middle silk gland cells and therefore likely directs organ-specific, but not territory-specific, expression. Developmental studies throughout the fourth larval molt, at which the P25 gene status changes from derepressed to repressed, revealed that BMFA is reversibly modified at the transition from intermolt to molt. Indeed, the preexisting BMFA is replaced by a structurally related factor, BMFA', during the 2 h following head capsule apolysis. The exact temporal coincidence of this conversion with the onset of gene repression suggests that BMFA' is involved in transcription inactivation and likely results from a transduction process initiated by the hormonal change at molting.
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Affiliation(s)
- B Durand
- Centre de Génétique Moléculaire et Cellulaire, UMR CNRS 106, Université Claude Bernard Lyon 1, Villeurbanne, France
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49
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Hui CC, Matsuno K, Ueno K, Suzuki Y. Molecular characterization and silk gland expression of Bombyx engrailed and invected genes. Proc Natl Acad Sci U S A 1992; 89:167-71. [PMID: 1346065 PMCID: PMC48197 DOI: 10.1073/pnas.89.1.167] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Genetic analysis in Drosophila has shown that engrailed (en) plays an important role in segmentation and neurogenesis. A closely related gene, invected (in), is coexpressed with en in the posterior developmental compartments where en is known to specify cell state. We report here the isolation of two en-like cDNAs from the middle silk glands of Bombyx mori larvae. Sequence analysis revealed that they are the counterparts of Drosophila en and in. Four highly conserved domains, including the homeodomain, were identified in these En and In proteins from Bombyx and Drosophila. In addition, two en-specific and one in-specific domains could also be found. These structurally homologous genes might share a similar role in Bombyx development. They were found to be coexpressed in the middle silk gland but not in the posterior silk gland during the fourth molt/fifth intermolt period. We speculate that these Bombyx en-like genes might be involved in the compartmentalization of the silk gland.
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Affiliation(s)
- C C Hui
- Department of Developmental Biology, National Institute for Basic Biology, Okazaki, Japan
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50
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Expression of a cytoplasmic actin gene in relation to the silk production cycle in the silk glands of Bombyx mori. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/0020-1790(91)90019-b] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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