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Rouhová L, Podlahová Š, Kmet P, Žurovec M, Sehadová H, Sauman I. A comprehensive gene expression analysis of the unique three-layered cocoon of the cecropia moth, Hyalophora cecropia. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2024; 171:104152. [PMID: 38944399 DOI: 10.1016/j.ibmb.2024.104152] [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: 12/08/2023] [Revised: 06/25/2024] [Accepted: 06/26/2024] [Indexed: 07/01/2024]
Abstract
The larvae of the moth Hyalophora cecropia spin silk cocoons with morphologically distinct layers. We investigated the expression of the individual silk protein components of these cocoons in relation to the morphology of the silk gland and its affiliation to the different layers of the cocoon. The study used transcriptomic and proteomic analyses to identify 91 proteins associated with the silk cocoons, 63 of which have a signal peptide indicating their secretory nature. We checked the specificity of their expression in different parts of the SG and the presence of the corresponding protein products in each cocoon layer. Differences were observed among less abundant proteins with unclear functions. The representation of proteins in the inner envelope and intermediate space was similar, except for a higher proportion of probable contaminating proteins, mostly originating from the gut. On the other hand, the outer envelope contains a number of putative enzymes with unclear function. However, the protein most specific to the outer layer has sequence homology to putative serine/threonine kinase-like proteins and some adhesive proteins, and its closest homolog in Bombyx mori was found in the scaffold silk. This research provides valuable insights into the silk production of the cecropia moth, highlighting both similarities and differences to other moth species.
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Affiliation(s)
- Lenka Rouhová
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic
| | - Šárka Podlahová
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic
| | - Peter Kmet
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic
| | - Michal Žurovec
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic.
| | - Hana Sehadová
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic.
| | - Ivo Sauman
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic.
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Kludkiewicz B, Kucerova L, Konikova T, Strnad H, Hradilova M, Zaloudikova A, Sehadova H, Konik P, Sehnal F, Zurovec M. The expansion of genes encoding soluble silk components in the greater wax moth, Galleria mellonella. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 106:28-38. [PMID: 30448349 DOI: 10.1016/j.ibmb.2018.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 11/14/2018] [Indexed: 06/09/2023]
Abstract
Lepidopteran silk is a complex assembly of proteins produced by a pair of highly specialized labial glands called silk glands. Silk composition has been examined only in a handful of species. Here we report on the analysis of silk gland-specific transcriptomes from three developmental stages of the greater wax moth, Galleria mellonella, combined with proteomics, Edman microsequencing and northern blot analysis. In addition to the genes known earlier, we identified twenty seven candidate cDNAs predicted to encode secretory proteins, which may represent novel silk components. Eight were verified by proteomic analysis or microsequencing, and several others were confirmed by similarity with known silk genes and their expression patterns. Our results revealed that most candidates encode abundant secreted proteins produced by middle silk glands including ten sericins, two seroins, one or more mucins, and several sequences without apparent similarity to known proteins. We did not detect any novel PSG-specific protein, confirming that there are only three fibroin subunits. Our data not only show that the number of sericin genes in the greater wax moth is higher than in other species thus far examined, but also the total content of soluble proteins in silk is twice as high in G. mellonella than in B. mori or A. yamamai. Our data will serve as a foundation for future identification and evolutionary analysis of silk proteins in the Lepidoptera.
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Affiliation(s)
- Barbara Kludkiewicz
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic
| | - Lucie Kucerova
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic
| | - Tereza Konikova
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic
| | - Hynek Strnad
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20, Praha 4, Czech Republic
| | - Miluse Hradilova
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20, Praha 4, Czech Republic
| | - Anna Zaloudikova
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic
| | - Hana Sehadova
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic
| | - Peter Konik
- Faculty of Science, University of South Bohemia, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic
| | - Frantisek Sehnal
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic; Faculty of Science, University of South Bohemia, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic.
| | - Michal Zurovec
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic; Faculty of Science, University of South Bohemia, Branisovska 31, 370 05, Ceske Budejovice, Czech Republic.
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Dong Z, Song Q, Zhang Y, Chen S, Zhang X, Zhao P, Xia Q. Structure, evolution, and expression of antimicrobial silk proteins, seroins in Lepidoptera. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2016; 75:24-31. [PMID: 27180727 DOI: 10.1016/j.ibmb.2016.05.005] [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: 12/01/2015] [Revised: 04/20/2016] [Accepted: 05/12/2016] [Indexed: 06/05/2023]
Abstract
The silks of silkworm and waxworm contain abundant antimicrobial proteins, including protease inhibitors and seroins. Protease inhibitors have antifungal activities, whereas seroins have antiviral and antibacterial activities. In order to obtain insights into the structure, evolution, and expression of seroins, we performed an extensive survey based on the available genome, transcriptome, and expressed sequence tags datasets. Sixty-four seroins were identified in 32 lepidopteran species. The phylogenetic and structural analyses revealed that seroins can be classified into five subfamilies: seroin 1, seroin 2, seroin 3, seroin 2 + 1, and seroin 3 + 3. It is interesting that seroin 2 + 1 contains two tandem seroin domains, seroin 2 and seroin 1, whereas seroin 3 + 3 has two tandem seroin 3 domains. Each seroin domain contains a proline-rich N-terminal motif and a conserved C-terminal motif. The transcriptome and EST data indicated that seroin 1 and seroin 2 genes were expressed in the silk gland but seroin 3 genes were not. Semi-quantitative RT-PCR and western blot analyses suggested that seroin 1 and seroin 2 were constantly accumulated in the silk gland of silkworm during the fifth instar, and then secreted into cocoon silk during spinning. Immunofluorescence analyses indicated that seroin 1 was secreted into the fibroin and sericin layers, whereas seroin 2 protein was only secreted into the sericin layer. However, the antimicrobial activity of seroin 2 was more effective than that of seroin 1. The presence of seroin 1 in the fibroin layer suggested that this protein not only acts as an antimicrobial protein, but might also play a role in the assembly and secretion of fibroins. Seroin 3, which was first identified here, might be related to pheromone synthesis or recognition, as it was highly expressed in male antennae and in the pheromone gland.
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Affiliation(s)
- Zhaoming Dong
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China
| | - Qianru Song
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China
| | - Yan Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China
| | - Shiyi Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China
| | - Xiaolu Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China
| | - Ping Zhao
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China.
| | - Qingyou Xia
- State Key Laboratory of Silkworm Genome Biology, Southwest University, 216, Tiansheng Road, Beibei, Chongqing 400716, China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, 2, Tiansheng Road, Beibei, Chongqing 400716, China
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Zurovec M, Yonemura N, Kludkiewicz B, Sehnal F, Kodrik D, Vieira LC, Kucerova L, Strnad H, Konik P, Sehadova H. Sericin Composition in the Silk of Antheraea yamamai. Biomacromolecules 2016; 17:1776-87. [PMID: 27049111 DOI: 10.1021/acs.biomac.6b00189] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The silks produced by caterpillars consist of fibroin proteins that form two core filaments, and sericin proteins that seal filaments into a fiber and conglutinate fibers in the cocoon. Sericin genes are well-known in Bombyx mori (Bombycidae) but have received little attention in other insects. This paper shows that Antheraea yamamai (Saturniidae) contains five sericin genes very different from the three sericin genes of B. mori. In spite of differences, all known sericins are characterized by short exons 1 and 2 (out of 3-12 exons), expression in the middle silk gland section, presence of repeats with high contents of Ser and charged amino acid residues, and secretion as a sticky silk component soluble in hot water. The B. mori sericins represent tentative phylogenetic lineages (I) BmSer1 and orthologs in Saturniidae, (II) BmSer2, and (III) BmSer3 and related sericins of Saturniidae and of the pyralid Galleria mellonella. The lineage (IV) seems to be limited to Saturniidae. Concerted evolution of the sericin genes was apparently associated with gene amplifications as well as gene loses. Differences in the silk fiber morphology indicate that the cocktail of sericins linking the filaments and coating the fiber is modified during spinning. Silks are composite biomaterials of conserved function in spite of great diversity of their composition.
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Affiliation(s)
- Michal Zurovec
- Entomological Institute, Biology Centre ASCR , Branišovská 31, 370 05 České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia , Branišovská 1760, 370 05 České Budějovice, Czech Republic
| | - Naoyuki Yonemura
- National Institute of Agrobiological Sciences Tsukuba , Ibaraki 305-8634, Japan
| | - Barbara Kludkiewicz
- Entomological Institute, Biology Centre ASCR , Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - František Sehnal
- Entomological Institute, Biology Centre ASCR , Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Dalibor Kodrik
- Entomological Institute, Biology Centre ASCR , Branišovská 31, 370 05 České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia , Branišovská 1760, 370 05 České Budějovice, Czech Republic
| | - Ligia Cota Vieira
- Entomological Institute, Biology Centre ASCR , Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Lucie Kucerova
- Entomological Institute, Biology Centre ASCR , Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Hynek Strnad
- Institute of Molecular Genetics ASCR , Vídeňská 1083, 142 20 Praha 4, Czech Republic
| | - Peter Konik
- Faculty of Science, University of South Bohemia , Branišovská 1760, 370 05 České Budějovice, Czech Republic
| | - Hana Sehadova
- Entomological Institute, Biology Centre ASCR , Branišovská 31, 370 05 České Budějovice, Czech Republic
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Differential Scanning Fluorimetry provides high throughput data on silk protein transitions. Sci Rep 2014; 4:5625. [PMID: 25004800 PMCID: PMC4088128 DOI: 10.1038/srep05625] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 06/16/2014] [Indexed: 11/08/2022] Open
Abstract
Here we present a set of measurements using Differential Scanning Fluorimetry (DSF) as an inexpensive, high throughput screening method to investigate the folding of silk protein molecules as they abandon their first native melt conformation, dehydrate and denature into their final solid filament conformation. Our first data and analyses comparing silks from spiders, mulberry and wild silkworms as well as reconstituted ‘silk' fibroin show that DSF can provide valuable insights into details of silk denaturation processes that might be active during spinning. We conclude that this technique and technology offers a powerful and novel tool to analyse silk protein transitions in detail by allowing many changes to the silk solutions to be tested rapidly with microliter scale sample sizes. Such transition mechanisms will lead to important generic insights into the folding patterns not only of silks but also of other fibrous protein (bio)polymers.
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Holland C, Porter D, Vollrath F. Comparing the rheology of mulberry and “wild” silkworm spinning dopes. Biopolymers 2011; 97:362-7. [DOI: 10.1002/bip.22011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 10/14/2011] [Accepted: 11/14/2011] [Indexed: 11/11/2022]
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Collin MA, Mita K, Sehnal F, Hayashi CY. Molecular evolution of lepidopteran silk proteins: insights from the ghost moth, Hepialus californicus. J Mol Evol 2010; 70:519-29. [PMID: 20458474 PMCID: PMC2876269 DOI: 10.1007/s00239-010-9349-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Accepted: 04/19/2010] [Indexed: 11/24/2022]
Abstract
Silk production has independently evolved in numerous arthropod lineages, such as Lepidoptera, the moths and butterflies. Lepidopteran larvae (caterpillars) synthesize silk proteins in modified salivary glands and spin silk fibers into protective tunnels, escape lines, and pupation cocoons. Molecular sequence data for these proteins are necessary to determine critical features of their function and evolution. To this end, we constructed an expression library from the silk glands of the ghost moth, Hepialus californicus, and characterized light chain fibroin and heavy chain fibroin gene transcripts. The predicted H. californicus silk fibroins share many elements with other lepidopteran and trichopteran fibroins, such as conserved placements of cysteine, aromatic, and polar amino acid residues. Further comparative analyses were performed to determine site-specific signatures of selection and to assess whether fibroin genes are informative as phylogenetic markers. We found that purifying selection has constrained mutation within the fibroins and that light chain fibroin is a promising molecular marker. Thus, by characterizing the H. californicus fibroins, we identified key functional amino acids and gained insight into the evolutionary processes that have shaped these adaptive molecules.
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Affiliation(s)
- Matthew A Collin
- Department of Biology, University of California, Riverside, CA 92521, USA.
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Zheng Z, Wei Y, Yan S, Li M. Preparation of regeneratedAntheraea yamamaisilk fibroin film and controlled-molecular conformation changes by aqueous ethanol treatment. J Appl Polym Sci 2010. [DOI: 10.1002/app.31522] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Yonemura N, Mita K, Tamura T, Sehnal F. Conservation of silk genes in Trichoptera and Lepidoptera. J Mol Evol 2009; 68:641-53. [PMID: 19449053 PMCID: PMC2691926 DOI: 10.1007/s00239-009-9234-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2008] [Revised: 04/07/2009] [Accepted: 04/08/2009] [Indexed: 12/02/2022]
Abstract
Larvae of the sister orders Trichoptera and Lepidoptera are characterized by silk secretion from a pair of labial glands. In both orders the silk filament consists of heavy (H)- and light (L)-chain fibroins and in Lepidoptera it also includes a P25 glycoprotein. The L-fibroin and H-fibroin genes of Rhyacophila obliterata and Hydropsyche angustipennis caddisflies have exon/intron structuring (seven exons in L-fibroin and two in H-fibroin) similar to that in their counterparts in Lepidoptera. Fibroin cDNAs are also known in Limnephilus decipiens, representing the third caddisfly suborder. Amino acid sequences of deduced L-fibroin proteins and of the terminal H-fibroin regions are about 50% identical among the three caddisfly species but their similarity to lepidopteran fibroins is <25%. Positions of some residues are conserved, including cysteines that were shown to link the L-fibroin and H-fibroin by a disulfide bridge in Lepidoptera. The long internal part of H-fibroins is composed of short motifs arranged in species-specific repeats. They are extremely uniform in R. obliterata. Motifs (SX)n, GGX, and GPGXX occur in both Trichoptera and Lepidoptera. The trichopteran H-fibroins further contain charged amphiphilic motifs but lack the strings of alanines or alanine-glycine dipeptides that are typical lepidopteran motifs. On the other hand, sequences composed of a motif similar to ERIVAPTVITR surrounded by the (SX)4-6 strings and modifications of the GRRGWGRRG motif occur in Trichoptera and not in Lepidoptera.
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Affiliation(s)
- Naoyuki Yonemura
- National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8634, Japan
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Xu S, Liu D, Li W. Upregulated proteins associated with fibroin synthesis in posterior silk glands of Antheraea pernyi fifth instar larvae. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2008; 4:105-10. [PMID: 20403748 DOI: 10.1016/j.cbd.2008.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 12/09/2008] [Accepted: 12/09/2008] [Indexed: 10/21/2022]
Abstract
Antheraea pernyi is a typical wild silkworm with larval silk glands specific for the synthesis and secretion of silk proteins. We examined changes in the protein profile in the posterior section of the silk glands on days 1 and 4 of the last larval instar. Two-dimensional gel electrophoresis over the pH range of 4-7 followed by silver staining revealed about 350 protein spots. Twenty-three proteins upregulated on day 4 were analyzed using matrix-assisted laser desorption/ionization time-of-flight/time-of-flight (MALDI-TOF/TOF). Search for homologous sequences in NCBI databases identified seven proteins probably involved in the regulation of transcription, translation, and general cell metabolism. Among these, glutathione S-transferase theta (GSTT) and ribosomal protein L8 (RPL8) were selected for investigations at the mRNA level. Real-time quantitative PCR showed that the expression of GSTT peaked on day 4, whereas that of RPL8 peaked on day 3, confirming the upregulation of these proteins during the last larval instar. These results show that expressions of GSTT and RPL8 may play a role in fibroin synthesis in A. pernyi.
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Affiliation(s)
- Shurong Xu
- School of Environmental and Biological Science and Technology, Dalian University of Technology, RP116023, Dalian, China
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Yonemura N, Sehnal F. The Design of Silk Fiber Composition in Moths Has Been Conserved for More Than 150 Million Years. J Mol Evol 2006; 63:42-53. [PMID: 16755355 DOI: 10.1007/s00239-005-0119-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2005] [Accepted: 08/01/2005] [Indexed: 11/26/2022]
Abstract
The silk of caterpillars is secreted in the labial glands, stored as a gel in their lumen, and converted into a solid filament during spinning. Heavy chain fibroin (H-fibroin), light chain fibroin (L-fibroin), and P25 protein constitute the filament core in a few species that have been analyzed. Identification of these proteins in Yponomeuta evonymella, a moth from a family which diverged from the rest of Lepidoptera about 150 million years ago, reveals that the mode of filament construction is highly conserved. It is proposed that association of the three proteins is suited for long storage of hydrated silk dope and its rapid conversion to filament. Interactions underlying these processes depend on conserved spacing of critical amino acid residues that are dispersed through the L-fibroin and P25 and assembled in the short ends of the H-fibroin molecule. Strength, elasticity, and other physical properties of the filament are determined by simple amino acid motifs arranged in repetitive modules that build up most of the H-fibroin. H-Fibroin synergy with L-fibroin and P25 does not interfere with motif diversification by which the filament acquires new properties. Several types of motifs in complex repeats occur in the silks used for larval cobwebs and pupal cocoons. Restriction of silk use to cocoon construction in some lepidopteran families has been accompanied by simplification of H-fibroin repeats. An extreme deviation of the silk structure occurs in the Saturniidae silkmoths, which possess modified H-fibroin and lack L-fibroin and P25.
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Affiliation(s)
- Naoyuki Yonemura
- Institute of Entomology and Faculty of Biological Sciences, Academy of Sciences, University of South Bohemia, Branisovská 31, 370 05, Ceské Budejovice, Czech Republic
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Abstract
The formation and properties of lepidopteran silk fibers depend on amino acid repeats in the principal protein, heavy chain fibroin (H-fibroin). In H-fibroins of the "bombycoid" type, concatenations of alanine or of the GAGAGS crystalline motifs (1st tier repeats) and adjacent sequences breaking periodicity make 2nd tier repeats. Two to six such repeats comprise a 3rd tier assembly, and 12 assemblies, linked by an amorphous sequence, constitute the repetitive H-fibroin region. Heterogeneity in the repeat length and intercalation of amorphous regions prevent excessive crystallization. In the "pyraloid" H-fibroins, iterations of simple motifs are absent and assemblies of several complex motifs constitute highly regular repeats that are organized in about 12 highest order reiterations without specific spacers. Repeat homogeneity appears crucial for the alignment and interaction of the disjunct motifs that must be registered precisely to form crystallites; repeat heterogeneity is associated with decreased fiber strength. Both H-fibroin types are typically hydrophobic, and their secretion requires disulfide linkage to light chain fibroin and participation of another protein, P25. These auxiliary proteins are absent in saturniid moths with amphiphilic H-fibroin repeats. The selection at nucleic acid and protein levels and the availability of nutrients play roles in H-fibroin evolution.
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Affiliation(s)
- Frantisek Sehnal
- Entomological Institute, Academy of Sciences, Branisovská 31, 370 05 Ceské Budejovice, Czech Republic.
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Fedic R, Zurovec M, Sehnal F. Correlation between fibroin amino acid sequence and physical silk properties. J Biol Chem 2003; 278:35255-64. [PMID: 12816957 DOI: 10.1074/jbc.m305304200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The fiber properties of lepidopteran silk depend on the amino acid repeats that interact during H-fibroin polymerization. The aim of our research was to relate repeat composition to insect biology and fiber strength. Representative regions of the H-fibroin genes were sequenced and analyzed in three pyralid species: wax moth (Galleria mellonella), European flour moth (Ephestia kuehniella), and Indian meal moth (Plodia interpunctella). The amino acid repeats are species-specific, evidently a diversification of an ancestral region of 43 residues, and include three types of regularly dispersed motifs: modifications of GSSAASAA sequence, stretches of tripeptides GXZ where X and Z represent bulky residues, and sequences similar to PVIVIEE. No concatenations of GX dipeptide or alanine, which are typical for Bombyx silkworms and Antheraea silk moths, respectively, were found. Despite different repeat structure, the silks of G. mellonella and E. kuehniella exhibit similar tensile strength as the Bombyx and Antheraea silks. We suggest that in these latter two species, variations in the repeat length obstruct repeat alignment, but sufficiently long stretches of iterated residues get superposed to interact. In the pyralid H-fibroins, interactions of the widely separated and diverse motifs depend on the precision of repeat matching; silk is strong in G. mellonella and E. kuehniella, with 2-3 types of long homogeneous repeats, and nearly 10 times weaker in P. interpunctella, with seven types of shorter erratic repeats. The high proportion of large amino acids in the H-fibroin of pyralids has probably evolved in connection with the spinning habit of caterpillars that live in protective silk tubes and spin continuously, enlarging the tubes on one end and partly devouring the other one. The silk serves as a depot of energetically rich and essential amino acids that may be scarce in the diet.
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Affiliation(s)
- Robert Fedic
- Institute of Entomology, Academy of Sciences and Faculty of Biological Sciences, University of South Bohemia, Branisovská, Ceské Budjejovice, Czech Republic
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Craig CL, Riekel C. Comparative architecture of silks, fibrous proteins and their encoding genes in insects and spiders. Comp Biochem Physiol B Biochem Mol Biol 2002; 133:493-507. [PMID: 12470814 DOI: 10.1016/s1096-4959(02)00095-7] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The known silk fibroins and fibrous glues are thought to be encoded by members of the same gene family. All silk fibroins sequenced to date contain regions of long-range order (crystalline regions) and/or short-range order (non-crystalline regions). All of the sequenced fibroin silks (Flag or silk from flagelliform gland in spiders; Fhc or heavy chain fibroin silks produced by Lepidoptera larvae) are made up of hierarchically organized, repetitive arrays of amino acids. Fhc fibroin genes are characterized by a similar molecular genetic architecture of two exons and one intron, but the organization and size of these units differs. The Flag, Ser (sericin gene) and BR (Balbiani ring genes; both fibrous proteins) genes are made up of multiple exons and introns. Sequences coding for crystalline and non-crystalline protein domains are integrated in the repetitive regions of Fhc and MA exons, but not in the protein glues Ser1 and BR-1. Genetic 'hot-spots' promote recombination errors in Fhc, MA, and Flag. Codon bias, structural constraint, point mutations, and shortened coding arrays may be alternative means of stabilizing precursor mRNA transcripts. Differential regulation of gene expression and selective splicing of the mRNA transcript may allow rapid adaptation of silk functional properties to different physical environments.
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Affiliation(s)
- Catherine L Craig
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA.
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16
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Zurovec M, Sehnal F. Unique molecular architecture of silk fibroin in the waxmoth, Galleria mellonella. J Biol Chem 2002; 277:22639-47. [PMID: 11886872 DOI: 10.1074/jbc.m201622200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteins of silk fibers are characterized by reiterations of amino acid repeats. Physical properties of the fiber are determined by the amino acid composition, the complexity of repetitive units, and arrangement of these units into higher order arrays. Except for very short motifs of 6-10 residues, the length of repetitive units and the number of these units concatenated in higher order assemblies vary in all spider and lepidopteran silks analyzed so far. This paper describes an exceptional silk protein represented by the 500-kDa heavy chain fibroin (H-fibroin) of the waxmoth, Galleria mellonella. Its non-repetitive N-terminal (175 residues) and C-terminal (60 residues) parts, the overall gene organization, and the nucleotide sequence around the TATA box show that it is homologous to the H-fibroins of other Lepidoptera. However, over 95% of the protein consists of highly ordered repetitive structures that are unmatched in other species. The repetitive region includes 11 assemblies AB(1)AB(1)AB(1)AB(2)(AB(2))AB(2) of remarkably conserved polypeptide repeats A (63 amino acid residues), B(1) (43 residues), and B(2) (18 residues). The repeats contain a high proportion of Gly (31.6%), Ala (23.8%), Ser (18.1%), and of residues with long hydrophobic side chains (16% for Leu, Ile, and Val combined). The presence of the GLGGLG and SSAASAA(AA) motifs suggests formation of pleated beta-sheets and their stacking into crystallites. Conspicuous conservation of the apolar sequence VIVI followed by DD or ED is interpreted as indicating the importance of hydrophobicity and electrostatic charge in H-fibroin cross-linking. The environment of G. mellonella larvae within bee cultures requires continuous production of silk that must be both strong and elastic. The spectacular arrangement of the repetitive H-fibroin region apparently evolved to meet these requirements.
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Affiliation(s)
- Michal Zurovec
- Institute of Entomology, Academy of Sciences, and the Faculty of Biological Sciences, University of South Bohemia, Branisovská 31, 370 05 Ceské Budejovice, Czech Republic
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Datta A, Ghosh AK, Kundu SC. Purification and characterization of fibroin from the tropical Saturniid silkworm, Antheraea mylitta. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2001; 31:1013-1018. [PMID: 11483437 DOI: 10.1016/s0965-1748(01)00049-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The fibroin protein isolated from the posterior silkgland of the tropical Saturniid silkworm Antheraea mylitta, was solubilized in lithium dodecyl sulfate and purified by gel filtration. The major fraction from gel filtration was analyzed by SDS-PAGE under non-reducing and reducing conditions. One major protein band of ca 395 kDa was obtained under non-reducing conditions and a doublet band of approximately 197 kDa under reducing conditions. The appearance of a single spot in two-dimensional electrophoresis confirmed the purity of the protein indicating that it may be a homodimeric protein of two similar sized polypeptides. Amino acid composition analysis showed that, like other Saturniid fibroins, it is rich in glycine, alanine and serine amino acids. N-terminal amino acid sequence shows significant homology with other Antheraea species. The enzymatic deglycosylation analysis indicates that the fibroin protein is glycosylated and the oligosaccharides are O-linked to the protein backbone by N-acetylgalactoseamine moiety which conforms to a Core 1 mucin-type glycosylation pattern.
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Affiliation(s)
- A Datta
- Department of Biotechnology, Indian Institute of Technology, Kharagpur 721302, India
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18
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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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Tanaka K, Kajiyama N, Ishikura K, Waga S, Kikuchi A, Ohtomo K, Takagi T, Mizuno S. Determination of the site of disulfide linkage between heavy and light chains of silk fibroin produced by Bombyx mori. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1432:92-103. [PMID: 10366732 DOI: 10.1016/s0167-4838(99)00088-6] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The analysis of fibroin secretion-deficient 'naked-pupa' mutant silkworms has suggested that the disulfide linkage between heavy (H) and light (L) chains of fibroin, produced by the silkworm, Bombyx mori, is essential in its efficient large-scale secretion from the posterior silk gland cells. However, the site of disulfide-linkage between H- and L-chains has not been determined. In this study, cysteine residues involved in the single disulfide linkage between H- and L-chains were identified as the twentieth residue from the carboxyl terminus of H-chain (Cys-c20) and Cys-172 of L-chain by sequencing of genomic clones and peptide analysis. Furthermore, Cys-c4 (fourth residue from the carboxyl terminus) and Cys-c1 at the carboxyl terminus of H-chain were shown to form an intramolecular disulfide bond.
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Affiliation(s)
- K Tanaka
- Laboratory of Molecular Biology, Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan
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20
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Bénédet F, Bigot Y, Renault S, Pouzat J, Thibout E. Polypeptides of Acrolepiopsis assectella cocoon (Lepidoptera: Yponomeutoidea): an external host-acceptance kairomone for the parasitoid Diadromus pulchellus (Hymenoptera: Ichneumonidae). JOURNAL OF INSECT PHYSIOLOGY 1999; 45:375-384. [PMID: 12770363 DOI: 10.1016/s0022-1910(98)00136-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Contact kairomones are essential for host-acceptance behaviour by female parasitoids. In the solitary endoparasitoid wasp, Diadromus pulchellus, this behaviour depends mainly on compound(s) in the cocoon of their host, Acrolepiopsis assectella pupae. Extracts of empty cocoons and polypeptides extracted from cocoons were tested in acceptance behaviour assays using cotton fibre lures bearing extracts. Extractions with solvents of increasing polarity indicated that the active compounds were polar, while SDS-PAGE showed that four glycopolypeptides contained enough information to trigger host-acceptance behaviour in female wasps. This kairomonal activity was found to be due to the protein moieties, and was independent of any glycosylation. These four glycopolypeptides might be two variants of two soluble sericin-like polypeptides differing in their degree of glycosylation.
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Affiliation(s)
- F Bénédet
- Institut de Recherche sur la Biologie de l'Insecte, UPRESA-CNRS 6035, Faculté des Sciences, Parc de Grandmont, 37200, Tours, France
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21
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Hui CC, Matsuno K, Suzuki Y. Fibroin gene promoter contains a cluster of homeodomain binding sites that interact with three silk gland factors. J Mol Biol 1990; 213:651-70. [PMID: 2359119 DOI: 10.1016/s0022-2836(05)80253-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
By nuclease protection and mobility shift assays, we have shown that the 5' flanking sequence of the Bombyx mori fibroin gene, which is known to be required for a maximal level of transcription in vitro, contains five regions (A to E) that bind protein factors from the posterior silk gland extract. A silk gland-specific factor (SGF-1) and a ubiquitous factor (FBF-A1) were found to interact with the proximal A region, while the related B region can only bind SGF-1. The three distal regions (C, D and E) bind one posterior silk gland-specific factor (SGF-2) and two ubiquitous factors (SGF-3 and -4). SGF-1 might play an important role in the expression of silk protein genes because it also binds to a similar site in the sericin-1 gene and potential SGF-1 binding sites can be found in two other silk protein genes of Bombyx mori and the fibroin gene of Antheraea yamamai. The three distal regions for SGF-2, -3 and -4 contain ten base-pairs of A + T-rich repeats that resemble the consensus binding site (TCAATTAAAT) of a number of homeodomain proteins. The TAAT motif in the core of these regions is shown to be important for the binding of these three proteins and, as described elsewhere, two Drosophila homeodomain proteins, ZEN (zerknüllt) and EVE (even-skipped). Interestingly, SGF-3 appears to be a Bombyx octamer binding protein and may also be involved in the regulation of the sericin-1 gene. The possibility that the fibroin gene and other silk protein genes may be a group of target genes for some members of the homeobox gene family is discussed.
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Affiliation(s)
- C C Hui
- Department of Developmental Biology, National Institute for Basic Biology, Okazaki, Japan
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22
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Insect silk glands: their types, development and function, and effects of environmental factors and morphogenetic hormones on them. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/0020-7322(90)90022-h] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Isolation and characterization of fibroin mRNAs from the saturniid silkworms, Antheraea yamamai, Antheraea pernyi and Philosamia cynthia ricini. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/0020-1790(88)90021-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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