Mutation in Bombyx mori fibrohexamerin (P25) gene causes reorganization of rough endoplasmic reticulum in posterior silk gland cells and alters morphology of fibroin secretory globules in the silk gland lumen
Language English Country Great Britain, England Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
34102294
DOI
10.1016/j.ibmb.2021.103607
PII: S0965-1748(21)00090-4
Knihovny.cz E-resources
- Keywords
- BMSK0001030, BMSK0001060, ER stress, ER whorls, Gene editing, Targeted mutagenesis,
- MeSH
- Bombyx * genetics ultrastructure MeSH
- Endoplasmic Reticulum metabolism ultrastructure MeSH
- Fibroins genetics metabolism ultrastructure MeSH
- Silk * chemistry genetics MeSH
- Mutation MeSH
- Mutagenesis, Site-Directed methods MeSH
- Salivary Glands * cytology ultrastructure MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- fhx protein, Bombyx mori MeSH Browser
- Fibroins MeSH
- Silk * MeSH
Larvae of many lepidopteran species produce a mixture of secretory proteins, known as silk, for building protective shelters and cocoons. Silk consists of a water-insoluble silk filament core produced in the posterior silk gland (PSG) and a sticky hydrophilic coating produced by the middle silk gland (MSG). In Bombyx mori, the fiber core comprises three proteins: heavy chain fibroin (Fib-H), light chain fibroin (Fib-L) and fibrohexamerin (Fhx, previously referred to as P25). To learn more about the role of Fhx, we used transcription activator-like effector nuclease (TALEN) mutagenesis and prepared a homozygous line with a null mutation in the Fhx gene. Our characterization of cocoon morphology and silk quality showed that the mutation had very little effect. However, a detailed inspection of the secretory cells in the posterior silk gland (PSG) of mid-last-instar mutant larvae revealed temporary changes in the morphology of the endoplasmic reticulum. We also observed a morphological difference in fibroin secretory globules stored in the PSG lumen of Fhx mutants, which suggests that their fibroin complexes have a slightly lower solubility. Finally, we performed an LC-MS-based quantitative proteomic analysis comparing mutant and wild-type (wt) cocoon proteins and found a high abundance of a 16 kDa secretory protein likely involved in fibroin solubility. Overall, our study shows that whilst Fhx is dispensable for silk formation, it contributes to the stability of fibroin complexes during intracellular transport and affects the morphology of fibroin secretory globules in the PSG lumen.
Institute of Sericulture Iikura 1053 300 0324 Ami machi Ibaraki Japan
National Agriculture and Food Research Organization 1 2 Owashi Tsukuba Ibaraki 305 8634 Japan
References provided by Crossref.org
Characterization and comparative analysis of sericin protein 150 in Bombyx mori
