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Cao J, Tao C, Qin X, Wu K, Yang H, Liu C, Cheng T. PI3K-Akt-SGF1-Dimm pathway mediates the nutritional regulation of silk protein synthesis in Bombyx mori. Int J Biol Macromol 2024; 278:134650. [PMID: 39128739 DOI: 10.1016/j.ijbiomac.2024.134650] [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: 05/30/2024] [Revised: 08/04/2024] [Accepted: 08/08/2024] [Indexed: 08/13/2024]
Abstract
The efficient synthesis of silk protein is heavily reliant on the ingestion of massive nutrients during the peak growth phase in the silkworm. However, the molecular mechanism of nutritional regulation of silk protein synthesis remains unknown. In this study, we investigated the impact of nutrient deficiency on the synthesis of silk protein. Nutritional deficiency led to a reduction in silk yield, accompanied by decreased levels of silk proteins and fibroin heavy chain (FibH)-activating transcription factors SGF1 and Dimm. Furthermore, insulin enhanced the protein levels of SGF1 and Dimm, which can be attenuated by specific inhibitors of PI3K. Co-immunoprecipitation analysis showed that the nutrient pathway factor protein kinase B (Akt) could interact with SGF1 protein. Knockdown of Akt reduced the phosphorylation level of SGF1 and impedes its nuclear translocation. Further studies revealed that SGF1 was directly bound to Fkh site in the 22-43 region upstream of ATG of Dimm gene to activate its transcription. In conclusion, during the peak growth phase, nutrition promotes the massive synthesis of silk protein through the PI3K-Akt-SGF1-Dimm pathway. This study offers valuable insights into the efficient synthesis of silk proteins and establishes a theoretical foundation for improving silk yield.
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Affiliation(s)
- Jun Cao
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China
| | - Cuicui Tao
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China
| | - Xiaodan Qin
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China
| | - Keli Wu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China
| | - Hongguo Yang
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China
| | - Chun Liu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China.
| | - Tingcai Cheng
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China.
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2
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Li S, Lao J, Sun Y, Hua X, Lin P, Wang F, Shen G, Zhao P, Xia Q. CRISPR/Cas9-Mediated Editing of BmEcKL1 Gene Sequence Affected Silk Gland Development of Silkworms ( Bombyx mori). Int J Mol Sci 2024; 25:1907. [PMID: 38339188 PMCID: PMC10856159 DOI: 10.3390/ijms25031907] [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: 12/22/2023] [Revised: 02/02/2024] [Accepted: 02/02/2024] [Indexed: 02/12/2024] Open
Abstract
The silkworm (Bombyx mori) has served humankind through silk protein production. However, traditional sericulture and the silk industry have encountered considerable bottlenecks and must rely on major technological breakthroughs to keep up with the current rapid developments. The adoption of gene editing technology has nevertheless brought new hope to traditional sericulture and the silk industry. The long period and low efficiency of traditional genetic breeding methods to obtain high silk-yielding silkworm strains have hindered the development of the sericulture industry; the use of gene editing technology to specifically control the expression of genes related to silk gland development or silk protein synthesis is beneficial for obtaining silkworm strains with excellent traits. In this study, BmEcKL1 was specifically knocked out in the middle (MSGs) and posterior (PSGs) silk glands using CRISPR/Cas9 technology, and ΔBmEcKL1-MSG and ΔBmEcKL1-PSG strains with improved MSGs and PSGs and increased silk production were obtained. This work identifies and proves that BmEcKL1 directly or indirectly participates in silk gland development and silk protein synthesis, providing new perspectives for investigating silk gland development and silk protein synthesis mechanisms in silkworms, which is of great significance for selecting and breeding high silk-yielding silkworm varieties.
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Affiliation(s)
- Shimin Li
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China; (S.L.); (J.L.); (X.H.); (P.L.); (F.W.); (G.S.); (P.Z.)
| | - Junjie Lao
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China; (S.L.); (J.L.); (X.H.); (P.L.); (F.W.); (G.S.); (P.Z.)
| | - Yue Sun
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China; (S.L.); (J.L.); (X.H.); (P.L.); (F.W.); (G.S.); (P.Z.)
| | - Xiaoting Hua
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China; (S.L.); (J.L.); (X.H.); (P.L.); (F.W.); (G.S.); (P.Z.)
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400716, China
| | - Ping Lin
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China; (S.L.); (J.L.); (X.H.); (P.L.); (F.W.); (G.S.); (P.Z.)
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400716, China
| | - Feng Wang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China; (S.L.); (J.L.); (X.H.); (P.L.); (F.W.); (G.S.); (P.Z.)
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400716, China
| | - Guanwang Shen
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China; (S.L.); (J.L.); (X.H.); (P.L.); (F.W.); (G.S.); (P.Z.)
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400716, China
| | - Ping Zhao
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China; (S.L.); (J.L.); (X.H.); (P.L.); (F.W.); (G.S.); (P.Z.)
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400716, China
| | - Qingyou Xia
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China; (S.L.); (J.L.); (X.H.); (P.L.); (F.W.); (G.S.); (P.Z.)
- State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400716, China
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3
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Lao J, Sun H, Wang A, Wu M, Liu D, Zhang Y, Chen C, Xia Q, Ma S. Effect of eIF6 on the development of silk glands and silk protein synthesis of the silkworm, Bombyx mori. Int J Biol Macromol 2024; 256:128316. [PMID: 38000606 DOI: 10.1016/j.ijbiomac.2023.128316] [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: 10/19/2023] [Revised: 11/18/2023] [Accepted: 11/19/2023] [Indexed: 11/26/2023]
Abstract
The silkworm is a lepidopteran domesticated from the wild silkworm, mostly valued for its efficient synthesis of silk protein. This species' ability to spin silk has supported the 5500-year-old silk industry and the globally known "Silk Road", making the transformation of mulberry leaves into silk of great concern. Therefore, research on the silk-related genes of silkworms and their regulatory mechanisms has attracted increasing attention. Previous studies have revealed that domestic silk gland cells are endoreduplication cells, and their high-copy genome and special chromatin conformation provide conditions for the high expression of silk proteins. In this study, we systematically investigate the expression pattern of eukaryotic initiation factors (eIFs) and identified the eIF6 as a eukaryotic translation initiation factor involved in the synthesis of silk proteins. We generated an eIF6 gene deletion mutant strain of silkworm using the CRISPR/Cas9 system and investigated the function of eIF6 in silk gland development and silk protein synthesis. The results showed that deletion of eIF6 inhibited the individual development of silkworm larvae, inhibited the development of silk glands, and significantly reduced the cocoon layer ratio. Therefore, we elucidated the function of eIF6 in the development of silk glands and the synthesis of silk proteins, which is important for further elucidation of the developmental process of silk glands and the mechanism underlying the ultra-high expression of silk proteins.
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Affiliation(s)
- Junjie Lao
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China
| | - Hao Sun
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China
| | - Aoming Wang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China
| | - Mingke Wu
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China
| | - Dan Liu
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China
| | - Yan Zhang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China
| | - Chaojie Chen
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China
| | - Qingyou Xia
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China; State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400716, China.
| | - Sanyuan Ma
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400716, China; State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing 400716, China.
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Zhu M, Tong X, Qiu Q, Pan J, Wei S, Ding Y, Feng Y, Hu X, Gong C. Identification and characterization of extrachromosomal circular DNA in the silk gland of Bombyx mori. INSECT SCIENCE 2023; 30:1565-1578. [PMID: 36826848 DOI: 10.1111/1744-7917.13191] [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: 09/19/2022] [Revised: 01/30/2023] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
The silk gland cells of silkworm are special cells which only replicate DNA in the nucleus without cell division throughout the larval stage. The extrachromosomal circular DNAs (eccDNAs) have not yet been reported in the silk gland of silkworms. Herein, we have explored the characterization of eccDNAs in the posterior silk gland of silkworms. A total of 35 346 eccDNAs were identified with sizes ranging from 30 to 13 569 549 bp. Motif analysis revealed that dual direct repeats are flanking the 5' and 3' breaking points of eccDNA. The sequences exceeding 1 kb length in eccDNAs present palindromic sequence characteristics flanking the 5' and 3' breaking points of the eccDNA. These motifs might support possible models for eccDNA generation. Genomic annotation of the eccDNA population revealed that most eccDNAs (58.6%) were derived from intergenic regions, whereas full or partial genes were carried by 41.4% of eccDNAs. It was found that silk protein genes fib-H, fib-L, and P25, as well as the transcription factors SGF and sage, which play an important regulatory role in silk protein synthesis, could be carried by eccDNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses showed that the genes carried by eccDNAs were mainly associated with the development and metabolism-related signaling pathways. Moreover, it was found that eccDNAfib-L could promote the transcription of fib-L gene. Overall, the results of the present study not only provide a novel perspective on the mechanism of silk gland development and silk protein synthesis but also complement previously reported genome-scale eccDNA data supporting that eccDNAs are common in eukaryotes.
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Affiliation(s)
- Min Zhu
- School of Biology & Basic Medical Science, Soochow University, Suzhou, China
| | - Xinyu Tong
- School of Biology & Basic Medical Science, Soochow University, Suzhou, China
| | - Qunnan Qiu
- School of Biology & Basic Medical Science, Soochow University, Suzhou, China
| | - Jun Pan
- School of Biology & Basic Medical Science, Soochow University, Suzhou, China
| | - Shulin Wei
- School of Biology & Basic Medical Science, Soochow University, Suzhou, China
| | - Yuming Ding
- School of Biology & Basic Medical Science, Soochow University, Suzhou, China
| | - Yongjie Feng
- School of Biology & Basic Medical Science, Soochow University, Suzhou, China
| | - Xiaolong Hu
- School of Biology & Basic Medical Science, Soochow University, Suzhou, China
- Institute of Agricultural Biotechnology and Ecological Research, Soochow University, Suzhou, China
| | - Chengliang Gong
- School of Biology & Basic Medical Science, Soochow University, Suzhou, China
- Institute of Agricultural Biotechnology and Ecological Research, Soochow University, Suzhou, China
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5
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Dynamics of nuclear matrix attachment regions during 5 th instar posterior silk gland development in Bombyx mori. BMC Genomics 2022; 23:247. [PMID: 35361117 PMCID: PMC8973518 DOI: 10.1186/s12864-022-08446-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 03/06/2022] [Indexed: 12/02/2022] Open
Abstract
Background Chromatin architecture is critical for gene expression during development. Matrix attachment regions (MARs) control and regulate chromatin dynamics. The position of MARs in the genome determines the expression of genes in the organism. In this study, we set out to elucidate how MARs temporally regulate the expression of the fibroin heavy chain (FIBH) gene during development. We addressed this by identifying MARs and studying their distribution and differentiation, in the posterior silk glands of Bombyx mori during 5th instar development. Results Of the MARs identified on three different days, 7.15% MARs were common to all 3 days, whereas, 1.41, 19.27 and 52.47% MARs were unique to day 1, day 5, and day 7, respectively highlighting the dynamic nature of the matrix associated DNA. The average chromatin loop length based on the chromosome wise distribution of MARs and the distances between these MAR regions decreased from day 1 (253.91 kb) to day 5 (73.54 kb) to day 7 (39.19 kb). Further significant changes in the MARs in the vicinity of the FIBH gene were found during different days of 5th instar development which implied their role in the regulation and expression of the FIBH gene. Conclusions The presence of MARs in the flanking regions of genes found to exhibit differential expression during 5th instar development indicates their possible role in the regulation of their expression. This reiterates the importance of MARs in the genomic functioning as regulators of the molecular mechanisms in the nucleus. This is the first study that takes into account the tissue specific genome-wide MAR association and the potential role of these MARs in developmentally regulated gene expression. The current study lays a foundation to understand the genome wide regulation of chromatin during development. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08446-3.
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Kitagawa T, Takiya S. Regulation of genes for ubiquitination and SUMO‐specific protease involved in larval development of the silkworm,
Bombyx mori. Dev Growth Differ 2020; 62:438-449. [DOI: 10.1111/dgd.12687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 05/26/2020] [Accepted: 05/30/2020] [Indexed: 11/30/2022]
Affiliation(s)
- Tsuyuki Kitagawa
- Graduate School of Life Science Hokkaido University Sapporo Japan
| | - Shigeharu Takiya
- Graduate School of Life Science Hokkaido University Sapporo Japan
- Division of Biological Sciences and Center for Genome Dynamics Faculty of Science Hokkaido University Sapporo Japan
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7
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Zhou QZ, Fu P, Li SS, Zhang CJ, Yu QY, Qiu CZ, Zhang HB, Zhang Z. A Comparison of Co-expression Networks in Silk Gland Reveals the Causes of Silk Yield Increase During Silkworm Domestication. Front Genet 2020; 11:225. [PMID: 32292415 PMCID: PMC7119365 DOI: 10.3389/fgene.2020.00225] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 02/26/2020] [Indexed: 12/24/2022] Open
Abstract
Long-term domestication and selective breeding have increased the silk yield of the domestic silkworm (Bombyx mori) by several times the amount of the silk yield of its wild ancestor (Bombyx mandarina). However, little is known about the molecular mechanisms behind the increase in silk yield during domestication. Based on dynamic patterns of functional divergence in the silk gland between domestic and wild silkworms, we found that at early and intermediate stages of silk gland development, the up-regulated genes of the domestic silkworm were mainly involved in DNA integration, nucleic acid binding, and transporter activity, which are related to the division and growth of cells. This has led to the posterior silk gland (PSG) of the domestic silkworm having significantly more cells (“factories” of fibroin protein synthesis) than that of the wild silkworm. At the late stage of silk gland development, the up-regulated genes in the domestic silkworm was enriched in protein processing and ribosome pathways, suggesting protein synthesis efficiency is greatly improved during silkworm domestication. While there was an increase in fibroin protein synthesis, the production of sericin protein was simultaneously reduced in the silk gland of the domestic silkworm. This reflects that domestic and wild silkworms have been under different selection pressures. Importantly, we found that the network co-expressed with the silk-coding genes of the domestic silkworm was larger than that of the wild silkworm. Furthermore, many more genes co-expressed with silk-coding genes in the domestic silkworm were subjected to artificial selection than those in the wild silkworm. Our results revealed that the increase of silk yield during silkworm domestication is involved in improvement of a biological system which includes not only expansion of “factories” (cells of PSG) of protein synthesis, but also a high expression of silk-coding genes and silk production-related genes such as biological energy, transport, and ribosome pathway genes.
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Affiliation(s)
- Qiu-Zhong Zhou
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing, China
| | - Ping Fu
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing, China.,Postdoctoral Station of Biomedical Engineering, Chongqing University, Chongqing, China
| | - Shu-Shang Li
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing, China
| | - Chang-Jiang Zhang
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing, China
| | - Quan-You Yu
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing, China
| | - Chuan-Zhen Qiu
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing, China
| | - Hong-Bo Zhang
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing, China
| | - Ze Zhang
- Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing, China
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8
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Zhao E, Jiang X, Cui H. Bombyx mori Dihydroorotate Dehydrogenase: Knockdown Inhibits Cell Growth and Proliferation via Inducing Cell Cycle Arrest. Int J Mol Sci 2018; 19:ijms19092581. [PMID: 30200251 PMCID: PMC6163951 DOI: 10.3390/ijms19092581] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/22/2018] [Accepted: 08/26/2018] [Indexed: 12/03/2022] Open
Abstract
Dihydroorotate dehydrogenase (DHODH), in the de novo pyrimidine biosynthetic pathway, is the fourth enzyme of pyrimidine synthesis and is used to oxidize dihydroorotate and hence to orotat. We cloned and characterized here the dhod of silkworms, Bombyx mori. The full-length cDNA sequence of dhod is 1339 bp, including an open reading frame (ORF) of 1173 bp that encoded a 390 amino acid protein. And two domains were involved in the Dihydroorotate dehydrogenase amino acid sequence of silkworms, Bombyx mori (BmDHODH), namely a DHO_dh domain and a transmembrane domain in N-termina. The silkworm dhod is expressed throughout development and in nine tissues. Moreover, knockdown of the silkworm dhod gene reduced cell growth and proliferation through G2/M phase cell cycle arrest. Similarly, DHODH inhibitor (leflunomide) also reduced cell growth and proliferation, with a significant decrease of cyclin B and cdk2. DHODH is the fourth enzyme of pyrimidine synthesis, so we also found that leflunomide can inhibit, at least in part, the endomitotic DNA replication in silk glands cells. These findings demonstrate that downregulation of BmDHODH inhibits cell growth and proliferation in silkworm cells, and the endomitotic DNA replication in silk gland cells.
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Affiliation(s)
- Erhu Zhao
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Chongqing 400716, China.
- Chongqing Engineering and Technology Research Center for Silk Biomaterials and Regenerative Medicine, Chongqing 400716, China.
- Southwest University Engineering Research Center for Cancer Biomedical and Translational Medicine, Southwest University, Chongqing 400715, China.
| | - Xiaolan Jiang
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Chongqing 400716, China.
| | - Hongjuan Cui
- State Key Laboratory of Silkworm Genome Biology, College of Biotechnology, Southwest University, Chongqing 400716, China.
- Chongqing Engineering and Technology Research Center for Silk Biomaterials and Regenerative Medicine, Chongqing 400716, China.
- Southwest University Engineering Research Center for Cancer Biomedical and Translational Medicine, Southwest University, Chongqing 400715, China.
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QTL analysis of cocoon shell weight identifies BmRPL18 associated with silk protein synthesis in silkworm by pooling sequencing. Sci Rep 2017; 7:17985. [PMID: 29269837 PMCID: PMC5740181 DOI: 10.1038/s41598-017-18277-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 12/07/2017] [Indexed: 01/17/2023] Open
Abstract
Mechanisms that regulate silk protein synthesis provide the basis for silkworm variety breeding and silk gland bioreactor optimization. Here, using the pooling sequencing-based methodology, we deciphered the genetic basis for the varied silk production in different silkworm strains. We identified 8 SNPs, with 6 on chromosome 11 and 1 each on chromosomes 22 and 23, that were linked with silk production. After conducting an association analysis between gene expression pattern, silk gland development and cocoon shell weight (CSW), BMGN011620 was found to be regulating silk production. BMGN011620 encodes the 60S ribosomal protein, L18, which is an indispensable component of the 60S ribosomal subunit; therefore we named it BmRPL18. Moreover, the clustering of linked SNPs on chromosome 11 and the analysis of differentially expressed genes reported in previous Omics studies indicated that the genes regulating silk protein synthesis may exhibit a clustering distribution in the silkworm genome. These results collectively advance our understanding of the regulation of silk production, including the role of ribosomal proteins and the clustered distribution of genes involved in silk protein synthesis.
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10
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Liu Y, Ma S, Chang J, Zhang T, Wang X, Shi R, Zhang J, Lu W, Liu Y, Xia Q. Tissue-specific genome editing of laminA/C in the posterior silk glands of Bombyx mori. J Genet Genomics 2017; 44:451-459. [DOI: 10.1016/j.jgg.2017.09.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 09/07/2017] [Accepted: 09/13/2017] [Indexed: 12/22/2022]
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11
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Zhang P, Liu S, Song HS, Zhang G, Jia Q, Li S. Yorkie CA overexpression in the posterior silk gland improves silk yield in Bombyx mori. JOURNAL OF INSECT PHYSIOLOGY 2017; 100:93-99. [PMID: 28583832 DOI: 10.1016/j.jinsphys.2017.06.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 06/01/2017] [Accepted: 06/01/2017] [Indexed: 06/07/2023]
Abstract
The traditional hybrid breeding techniques can no longer meet the increasing demands for silk production by the silkworm, Bombyx mori, and further improvement of the silk yield will depend on modern molecular breeding techniques. Here, we report improved silk yield in transgenic silkworms overexpressing the oncogene YorkieCA specifically in the posterior silk gland (PSG). The YorkieCA cDNA was ligated downstream of the hr3 enhancer and the fibroin L-chain (Fil) promoter, then inserted into a piggyBac vector for transgene. Overexpression of YorkieCA in the PSG significantly increased the weight of the PSG, and also increased the weight of the cocoon, larval body, and pupal body to decreasing degrees. Overexpression of YorkieCA up-regulated the Yorkie target genes resulting in increased cell size, endomitosis, the number of protein synthesis organelles, the expression of fibroin genes in the PSG, and eventually silk yield. Additionally, as we reported previously using the binary GAL4/UAS system, transgenic silkworms overexpressing Ras1CA with the hr3 enhancer and the Fil promoter also showed improved silk yield. Unfortunately, the hybrid progeny of YorkieCA-overexpressing silkworms and Ras1CA-overexpressing silkworms did not show overlapping improved silk yield due to the failure to increase expression of both Yorkie and Ras1.
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Affiliation(s)
- Panli Zhang
- College of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Shumin Liu
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Hong-Sheng Song
- College of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Guozheng Zhang
- College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212018, China
| | - Qiangqiang Jia
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Sciences and School of Life Sciences, South China Normal University, Guangzhou 510631, China.
| | - Sheng Li
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Sciences and School of Life Sciences, South China Normal University, Guangzhou 510631, China.
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12
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Differentially expressed genes in the silk gland of silkworm ( Bombyx mori ) treated with TiO 2 NPs. Gene 2017; 611:21-26. [DOI: 10.1016/j.gene.2017.02.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 02/14/2017] [Accepted: 02/15/2017] [Indexed: 10/20/2022]
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Chen RT, Jiao P, Liu Z, Lu Y, Xin HH, Zhang DP, Miao YG. Role of BmDredd during Apoptosis of Silk Gland in Silkworm, Bombyx mori. PLoS One 2017; 12:e0169404. [PMID: 28068357 PMCID: PMC5222620 DOI: 10.1371/journal.pone.0169404] [Citation(s) in RCA: 5] [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: 08/04/2016] [Accepted: 12/16/2016] [Indexed: 11/19/2022] Open
Abstract
Silk glands (SGs) undergo massive apoptosis driven degeneration during the larval-pupal transformation. To better understand this event on molecular level, we investigated the expression of apoptosis-related genes across the developmental transition period that spans day 4 in the fifth instar Bombyx mori larvae to day 2 pupae. Increases in the expression of BmDredd (an initiator caspase homolog) closely followed the highest BmEcR expression and resembled the expression trend of BmIcE. Simultaneously, we found that BmDredd expression was significantly higher in SG compared to other tissues at 18 h post-spinning, but reduced following injection of the apoptosis inhibitor (Z-DEVD-fmk). Furthermore, BmDredd expression correlated with changes of caspase3-like activities in SG and RNAi-mediated knockdown of BmDredd delayed SG apoptosis. Moreover, caspase3-like activity was increased in SG by overexpression of BmDredd. Taken together, the results suggest that BmDredd plays a critical role in SG apoptosis.
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Affiliation(s)
- Rui-ting Chen
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Peng Jiao
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Zhen Liu
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Yan Lu
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Hu-hu Xin
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Deng-pan Zhang
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Yun-gen Miao
- Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, People's Republic of China
- * E-mail:
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14
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Kunz RI, Brancalhão RMC, Ribeiro LDFC, Natali MRM. Silkworm Sericin: Properties and Biomedical Applications. BIOMED RESEARCH INTERNATIONAL 2016; 2016:8175701. [PMID: 27965981 PMCID: PMC5124675 DOI: 10.1155/2016/8175701] [Citation(s) in RCA: 193] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/05/2016] [Accepted: 10/12/2016] [Indexed: 01/23/2023]
Abstract
Silk sericin is a natural polymer produced by silkworm, Bombyx mori, which surrounds and keeps together two fibroin filaments in silk thread used in the cocoon. The recovery and reuse of sericin usually discarded by the textile industry not only minimizes environmental issues but also has a high scientific and commercial value. The physicochemical properties of the molecule are responsible for numerous applications in biomedicine and are influenced by the extraction method and silkworm lineage, which can lead to variations in molecular weight and amino acid concentration of sericin. The presence of highly hydrophobic amino acids and its antioxidant potential make it possible for sericin to be applied in the food and cosmetic industry. The moisturizing power allows indications as a therapeutic agent for wound healing, stimulating cell proliferation, protection against ultraviolet radiation, and formulating creams and shampoos. The antioxidant activity associated with low digestibility of sericin that expands the application in the medical field, such as antitumour, antimicrobial and anti-inflammatory agent, anticoagulant, acts in colon health, improving constipation and protects the body from obesity through improved plasma lipid profile. In addition, the properties of sericin allow its application as a culture medium and cryopreservation, in tissue engineering and for drug delivery, demonstrating its effective use, as an important biomaterial.
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Affiliation(s)
- Regina Inês Kunz
- Department of Morphological Sciences, State University of Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR, Brazil
| | - Rose Meire Costa Brancalhão
- Center of Biological Sciences and Health, State University of Western Paraná, Rua Universitária, 2069, 85819-110 Cascavel, PR, Brazil
| | - Lucinéia de Fátima Chasko Ribeiro
- Center of Biological Sciences and Health, State University of Western Paraná, Rua Universitária, 2069, 85819-110 Cascavel, PR, Brazil
| | - Maria Raquel Marçal Natali
- Department of Morphological Sciences, State University of Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR, Brazil
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15
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Gang X, Qian W, Zhang T, Yang X, Xia Q, Cheng D. Aurora B kinase is required for cell cycle progression in silkworm. Gene 2016; 599:60-67. [PMID: 27836666 DOI: 10.1016/j.gene.2016.11.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 10/20/2016] [Accepted: 11/07/2016] [Indexed: 11/30/2022]
Abstract
Aurora B kinase, a member of serine/threonine kinase family, is the catalytic subunit of the chromosomal passenger complex and is essential for chromosome alignment, chromosome segregation, and cytokinesis during mitosis. Here, we cloned the full-length cDNA sequence of silkworm Aurora B (BmAurB) gene and predicted that BmAurB protein contains a conserved S_TKc domain. Phylogenetic analysis between BmAurB and other Aurora kinases indicates that Aurora kinases may have evolved after separation between mammalian and insect, and prior to radiation of either mammalian or insects. RT-PCR examination revealed that the expression of the BmAurB gene was high in mitotic cycling gonads, moderate in mitotic cycling brain, and undetectable in endocycling silk gland during silkworm larval development. RNAi or inhibitor-mediated inhibition of the BmAurB gene in silkworm ovary-derived BmN4-SID1 cells disrupted cell cycle progression during mitosis and induced an accumulation of polyploid cells, cell cycle arrest at G2/M phase, chromosome misalignment, chromosome bridge, and bi-nucleation. Taken together, our results suggest that the BmAurB gene is required for cell cycle progression in silkworm.
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Affiliation(s)
- Xiaoxu Gang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Wenliang Qian
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Tianlei Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Xinxin Yang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China
| | - Daojun Cheng
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China.
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16
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Li YF, Chen XY, Zhang CD, Tang XF, Wang L, Liu TH, Pan MH, Lu C. Effects of starvation and hormones on DNA synthesis in silk gland cells of the silkworm, Bombyx mori. INSECT SCIENCE 2016; 23:569-578. [PMID: 25558018 DOI: 10.1111/1744-7917.12199] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/30/2014] [Indexed: 06/04/2023]
Abstract
Silk gland cells of silkworm larvae undergo multiple cycles of endomitosis for the synthesis of silk proteins during the spinning phase. In this paper, we analyzed the endomitotic DNA synthesis of silk gland cells during larval development, and found that it was a periodic fluctuation, increasing during the vigorous feeding phase and being gradually inhibited in the next molting phase. That means it might be activated by a self-regulating process after molting. The expression levels of cyclin E, cdt1 and pcna were consistent with these developmental changes. Moreover, we further examined whether these changes in endomitotic DNA synthesis resulted from feeding or hormonal stimulation. The results showed that DNA synthesis could be inhibited by starvation and re-activated by re-feeding, and therefore appears to be dependent on nutrition. DNA synthesis was suppressed by in vivo treatment with 20-hydroxyecdysone (20E). However, there was no effect on DNA synthesis by in vitro 20E treatment or by either in vivo or in vitro juvenile hormone treatment. The levels of Akt and 4E-BP phosphorylation in the silk glands were also reduced by starvation and in vivo treatment with 20E. These results indicate that the activation of endomitotic DNA synthesis during the intermolt stages is related to feeding and DNA synthesis is inhibited indirectly by 20E.
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Affiliation(s)
- Yao-Feng Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Xiang-Yun Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Chun-Dong Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Department of Biochemistry and Molecular Biology, Chongqing Medical University, Chongqing, China
| | - Xiao-Fang Tang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - La Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Tai-Hang Liu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Min-Hui Pan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Cheng Lu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
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17
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Dong Z, Zhao P, Zhang Y, Song Q, Zhang X, Guo P, Wang D, Xia Q. Analysis of proteome dynamics inside the silk gland lumen of Bombyx mori. Sci Rep 2016; 6:21158. [PMID: 27102218 PMCID: PMC4840313 DOI: 10.1038/srep21158] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 01/05/2016] [Indexed: 12/14/2022] Open
Abstract
The silk gland is the only organ where silk proteins are synthesized and secreted in the silkworm, Bombyx mori. Silk proteins are stored in the lumen of the silk gland for around eight days during the fifth instar. Determining their dynamic changes is helpful for clarifying the secretion mechanism of silk proteins. Here, we identified the proteome in the silk gland lumen using liquid chromatography-tandem mass spectrometry, and demonstrated its changes during two key stages. From day 5 of the fifth instar to day 1 of wandering, the abundances of fibroins, sericins, seroins, and proteins of unknown functions increased significantly in different compartments of the silk gland lumen. As a result, these accumulated proteins constituted the major cocoon components. In contrast, the abundances of enzymes and extracellular matrix proteins decreased in the silk gland lumen, suggesting that they were not the structural constituents of silk. Twenty-five enzymes may be involved in the regulation of hormone metabolism for proper silk gland function. In addition, the metabolism of other non-proteinous components such as chitin and pigment were also discussed in this study.
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Affiliation(s)
- Zhaoming Dong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China
| | - Ping Zhao
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China
| | - Yan Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China
| | - Qianru Song
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China
| | - Xiaolu Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China
| | - Pengchao Guo
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China
| | - Dandan Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China
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18
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Neiman M, Beaton MJ, Hessen DO, Jeyasingh PD, Weider LJ. Endopolyploidy as a potential driver of animal ecology and evolution. Biol Rev Camb Philos Soc 2015; 92:234-247. [PMID: 26467853 DOI: 10.1111/brv.12226] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 09/15/2015] [Accepted: 09/16/2015] [Indexed: 01/20/2023]
Abstract
Endopolyploidy - the existence of higher-ploidy cells within organisms that are otherwise of a lower ploidy level (generally diploid) - was discovered decades ago, but remains poorly studied relative to other genomic phenomena, especially in animals. Our synthetic review suggests that endopolyploidy is more common in animals than often recognized and probably influences a number of fitness-related and ecologically important traits. In particular, we argue that endopolyploidy is likely to play a central role in key traits such as gene expression, body and cell size, and growth rate, and in a variety of cell types, including those responsible for tissue regeneration, nutrient storage, and inducible anti-predator defences. We also summarize evidence for intraspecific genetic variation in endopolyploid levels and make the case that the existence of this variation suggests that endopolyploid levels are likely to be heritable and thus a potential target for natural selection. We then discuss why, in light of evident benefits of endopolyploidy, animals remain primarily diploid. We conclude by highlighting key areas for future research such as comprehensive evaluation of the heritability of endopolyploidy and the adaptive scope of endopolyploid-related traits, the extent to which endopolyploid induction incurs costs, and characterization of the relationships between environmental variability and endopolyploid levels.
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Affiliation(s)
- Maurine Neiman
- Department of Biology, University of Iowa, 143 Biology Building, Iowa City, IA 52242, U.S.A
| | - Margaret J Beaton
- Biology Department, Mount Allison University, Sackville, NB E4L 1G7, Canada
| | - Dag O Hessen
- Department of Biosciences, University of Oslo, Box 1066, Blindern, 0316 Oslo, Norway
| | - Punidan D Jeyasingh
- Department of Integrative Biology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK 74078, U.S.A
| | - Lawrence J Weider
- Department of Biology, Program in Ecology and Evolutionary Biology, University of Oklahoma, 730 Van Vleet Oval, Room 304, Norman, OK 73019, U.S.A
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19
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Domigan LJ, Andersson M, Alberti KA, Chesler M, Xu Q, Johansson J, Rising A, Kaplan DL. Carbonic anhydrase generates a pH gradient in Bombyx mori silk glands. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2015; 65:100-6. [PMID: 26365738 PMCID: PMC4628561 DOI: 10.1016/j.ibmb.2015.09.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 09/02/2015] [Accepted: 09/03/2015] [Indexed: 05/08/2023]
Abstract
Silk is a protein of interest to both biological and industrial sciences. The silkworm, Bombyx mori, forms this protein into strong threads starting from soluble silk proteins using a number of biochemical and physical cues to allow the transition from liquid to fibrous silk. A pH gradient has been measured along the gland, but the methodology employed was not able to precisely determine the pH at specific regions of interest in the silk gland. Furthermore, the physiological mechanisms responsible for the generation of this pH gradient are unknown. In this study, concentric ion selective microelectrodes were used to determine the luminal pH of B. mori silk glands. A gradient from pH 8.2 to 7.2 was measured in the posterior silk gland, with a pH 7 throughout the middle silk gland, and a gradient from pH 6.8 to 6.2 in the beginning of the anterior silk gland where silk processing into fibers occurs. The small diameter of the most anterior region of the anterior silk gland prevented microelectrode access in this region. Using a histochemical method, the presence of active carbonic anhydrase was identified in the funnel and anterior silk gland of fifth instar larvae. The observed pH gradient collapsed upon addition of the carbonic anhydrase inhibitor methazolamide, confirming an essential role for this enzyme in pH regulation in the B. mori silk gland. Plastic embedding of whole silk glands allowed clear visualization of the morphology, including the identification of four distinct epithelial cell types in the gland and allowed correlations between silk gland morphology and silk stages of assembly related to the pH gradient. B. mori silk glands have four different epithelial cell types, one of which produces carbonic anhydrase. Carbonic anhydrase is necessary for the mechanism that generates an intraluminal pH gradient, which likely regulates the assembly of silk proteins and then the formation of fibers from soluble silk proteins. These new insights into native silk formation may lead to a more efficient production of artificial or regenerated silkworm silk fibers.
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Affiliation(s)
- L J Domigan
- Department of Biomedical Engineering, Tufts University, Medford, MA, USA; School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - M Andersson
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - K A Alberti
- Department of Biomedical Engineering, Tufts University, Medford, MA, USA
| | - M Chesler
- Department of Neurosurgery, Physiology and Neuroscience, New York University School of Medicine, New York, NY, USA
| | - Q Xu
- Department of Biomedical Engineering, Tufts University, Medford, MA, USA
| | - J Johansson
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden; Department of Neurobiology, Care Sciences and Society, Karolinska Institute, Huddinge, Sweden; Institute of Mathematics and Natural Sciences, Tallinn University, Tallinn, Estonia
| | - A Rising
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden; Department of Neurobiology, Care Sciences and Society, Karolinska Institute, Huddinge, Sweden.
| | - D L Kaplan
- Department of Biomedical Engineering, Tufts University, Medford, MA, USA.
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20
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Li Y, Chen X, Tang X, Zhang C, Wang L, Chen P, Pan M, Lu C. DNA synthesis during endomitosis is stimulated by insulin via the PI3K/Akt and TOR signaling pathways in the silk gland cells of Bombyx mori. Int J Mol Sci 2015; 16:6266-80. [PMID: 25794286 PMCID: PMC4394531 DOI: 10.3390/ijms16036266] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/03/2015] [Accepted: 03/05/2015] [Indexed: 01/23/2023] Open
Abstract
Silk gland cells undergo multiple endomitotic cell cycles during silkworm larval ontogeny. Our previous study demonstrated that feeding is required for continued endomitosis in the silk gland cells of silkworm larvae. Furthermore, the insulin signaling pathway is closely related to nutritional signals. To investigate whether the insulin signaling pathway is involved in endomitosis in silk gland cells, in this study, we initially analyzed the effects of bovine insulin on DNA synthesis in endomitotic silk gland cells using 5-bromo-2'-deoxyuridine (BrdU) labeling technology, and found that bovine insulin can stimulate DNA synthesis. Insulin signal transduction is mainly mediated via phosphoinositide 3-kinase (PI3K)/Akt, the target of rapamycin (TOR) and the extracellular signal-regulated kinase (ERK) pathways in vertebrates. We ascertained that these three pathways are involved in DNA synthesis in endomitotic silk gland cells using specific inhibitors against each pathway. Moreover, we investigated whether these three pathways are involved in insulin-stimulated DNA synthesis in endomitotic silk gland cells, and found that the PI3K/Akt and TOR pathways, but not the ERK pathway, are involved in this process. These results provide an important theoretical foundation for the further investigations of the mechanism underlying efficient endomitosis in silk gland cells.
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Affiliation(s)
- Yaofeng Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
| | - Xiangyun Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
| | - Xiaofang Tang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
| | - Chundong Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
- Department of Biochemistry and Molecular Biology, Chongqing Medical University, Chongqing 400016, China.
| | - La Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
| | - Peng Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
| | - Minhui Pan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing 400716, China.
| | - Cheng Lu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China.
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing 400716, China.
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21
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Ji MM, Liu AQ, Gan LP, Xing R, Wang H, Sima YH, Xu SQ. Functional analysis of 30K proteins during silk gland degeneration by a caspase-dependent pathway in Bombyx. INSECT MOLECULAR BIOLOGY 2013; 22:273-283. [PMID: 23496335 DOI: 10.1111/imb.12019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The 30K proteins are involved with important functions in the growth and development of Bombyx mori. In this study, the synthesis and regulation of 30K proteins were examined during the degeneration of Bombyx silk glands. On day 3 of the fifth instar, the protein level of 30Kc19 was low, whereas the silk proteins were rapidly synthesized. However, synthesis and accumulation of the 30Kc19 protein significantly increased at the prepupal stage and on day 1 of the pupal stage. At this stage, the silk gland cells were filled with 30Kc19 and genomic DNA. Moreover, the transcript levels of the 30K-encoding genes, including 30Kc6, 30Kc12, 30Kc19 and 30Kc23 were up-regulated during the degeneration of the Bombyx silk glands. During the time that the levels of the 30Kc19 protein were significantly up-regulated, it is notable that the transcript levels of the BmAtg8, BmAtg6 and BmDronc genes dramatically increased to regulate the programmed cell death of this gland. On day 1 of the pupal stage, intense fragmentation of genomic DNA occurred in the silk gland cells, and the putative active form of caspase was detected in the cytoplasm, showing the complete degradation of the silk glands in one day. In conclusion, the 30K proteins are synthesized in high concentrations, while proteolysis mediates silk gland degeneration in Bombyx by a caspase-dependent pathway. We propose that the 30K proteins may be nutrients and energy vectors to be absorbed by the developing tissues of pupae or moths.
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Affiliation(s)
- M-M Ji
- Department of Applied Biology, School of Biology and Basic Medical Sciences, Medical College of Soochow University, Suzhou, China
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22
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BmCyclin B and BmCyclin B3 are required for cell cycle progression in the silkworm, Bombyx mori. SCIENCE CHINA-LIFE SCIENCES 2013; 56:360-5. [PMID: 23504272 DOI: 10.1007/s11427-013-4459-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 01/04/2013] [Indexed: 10/27/2022]
Abstract
Cyclin B is an important regulator of the cell cycle G2 to M phase transition. The silkworm genomic database shows that there are two Cyclin B genes in the silkworm (Bombyx mori), BmCyclin B and BmCyclin B3. Using silkworm EST data, the cyclin B3 (EU074796) gene was cloned. Its complete cDNA was 1665 bp with an ORF of 1536 bp derived from seven exons and six introns. The BmCyclin B3 gene encodes 511 amino acids, and the predicted molecular weight is 57.8 kD with an isoelectric point of 9.18. The protein contains one protein damage box and two cyclin boxes. RNA interference-mediated reduction of BmCyclin B and BmCyclin B3 expression induced cell cycle arrest in G2 or M phase in BmN-SWU1 cells, thus inhibiting cell proliferation. These results suggest that BmCyclin B and BmCyclin B3 are necessary for completing the cell cycle in silkworm cells.
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