Project description:The silkworm, Bombyx mori, is a complete metamorphosis insect and an economically important for silk production, the model to study insect physiology and biochemistry. Bombyx mori nucleopolyhedrovirus (BmNPV) is a principal pathogen of the silkworm and its host range is restricted to silkworm larvae, requiring interaction with silkworm larvae to accomplish virus replication. Prothoracic glands (PGs) are a model for synthetic ecdysone with regulating insect growth and development. In this study, day-4 fifth instar silkworm larvae were infected by BmNPV, the wandering silkworms appeared in the infected groups were 12 hours earlier than that in the control groups, and the ecdysone titer in infected larvae was significantly higher than that of the control larvae. Then, we used RNA sequencing (RNA-seq) to analyze silkworm PGs 48 h after BmNPV infection. The classifications of the 15 differential expression genes (DEGs) were mainly involved in the metabolic processes and pathways. The RT-qPCR results of the DEGs in the PGs of BmNPV-infected at 24, 48, and 72 h were generally consistent with the transcriptome data. The transcripts of BmTrypsin-1 and BmACSS3 were significantly increased from 24 to 72 h after BmNPV infection that they may be involved in the maturation process in the latter half of silkworm fifth instar larvae. These findings will help to address the interactions between BmNPV infection and host developmental response.
Project description:Background: MicroRNA (miRNA) and other small regulatory RNAs contribute to the modulation of a large number of cellular processes. We sequenced three total RNA libraries prepared from the whole body, and the anterior and posterior silk glands of Bombyx mori, with a view to expanding the repertoire of silkworm miRNAs and exploring transcriptional differences in miRNAs between segments of the silk gland. Results: With the aid of large-scale Solexa sequencing technology, we validated 244 unique miRNA genes, including 191 novel and 53 previously reported genes, corresponding to 309 loci in the silkworm genome. Interestingly, 24 unique miRNAs were widely conserved from invertebrates to vertebrates; 12 unique ones were limited to invertebrates and 33 were confined to insects; whereas the majority of the newly identified miRNAs were silkworm-specific. We identified 21 clusters and 42 paralogs of miRNAs in the silkworm genome. However, sequence tags showed that paralogs or clusters are not prerequisites for coordinated transcription and accumulation. The majority of silkworm-specific miRNAs are located in transposable elements, and display significant differences in abundance between the anterior and posterior silk glands. Conclusions: Conservative analysis revealed that miRNAs serve as phylogenetic markers and function in evolutionary signaling. The newly identified miRNAs greatly enriched the repertoire of insect miRNAs, and provide insights into miRNA evolution, biogenesis, and expression in insects. The differential expression of miRNAs in the anterior and posterior silk glands supports their involvement as new layers in the regulation of the silkworm silk gland. Sequencing three total RNA pools of the whole silkworm body from 5th-instar day-3 larvae, and anterior and posterior silkworm silk glands, using the latest sequencing Solexa technology
Project description:Microsporidia have attracted much attention because they infect a variety of species ranging from protists to mammals, including immunocompromised patients with AIDS or cancer. Aside from the study on Nosema ceranae, few works have focused on elucidating the mechanism in host response to microsporidia infection. Nosema bombycis is a pathogen of silkworm pM-CM-)brine that causes great economic losses to the silkworm industry. Detailed understanding of the host (Bombyx mori) response to infection by N. bombycis is helpful for prevention of this disease. The 23 K silkworm genome array was used to investigate host responses (i.e., Bombyx mori) occurring at 2, 4, 6 and 8 d post-infection by Nosema bombycis.We focused on elucidating the mechanism of the host response to microsporidia infection, especially for the investigation of host immune response . The third instar molted silkworm larvae were in oral infected by Nosema bombycis. In order to known the silkworm host response to Nosema bombycis infection at different time points, samples of infected larvae (i.e., the treatment set) and uninfected larvae (i.e., the control set) were collected at 2, 4, 6 and 8 dpi for RNA extraction and array hybridization. The obtained data were usd to investigate on the interplay of the genome-wide expression profile of hosts.
Project description:Insect NF-κB-like factor, Relish, is activated by viral infection and induces the production of antiviral proteins. In this study, we performed a transcriptomic analysis of BmE cells expressing the active form of BmRelish (BmRelishact) and identified BmVago as the most strongly-induced secreted-protein. Expression of Bmvago was specifically triggered by Bombyx mori nucleopolyhedrovirus (BmNPV) infection and regulated by BmSTING-BmRelish pathway. Incubating the fresh culture of cells with supernatant medium of BmVago-expressing cells or recombinant BmVago protein (rBmVago) significantly increased antiviral resistance. On the contrary, reducing the expression of Bmvago by RNA interference (RNAi) in BmE cells as well as in silkworm larvae impaired antiviral response. Furthermore, we constructed transgenic silkworm line over-expressing BmVago (BmVagoOV) and found they had markedly lower viral load and higher survival rate after BmNPV infection compared with the wild-type control. Co-immunoprecipitation assay showed Bmintegrin β1 interacts with BmVago and it was involved in BmVago-mediated antiviral response. Finally, we found the expression level of signaling molecules in Jak-Stat pathway increased in rBmVago-treated cells and BmVagoOV silkworm larvae but decreased in RNAi-treated cells. In summary, our research uncovered an inducible antiviral response in silkworm mediated by cytokine BmVago, which is the downstream effector of BmSTING-BmRelish pathway and functions as an antiviral cytokine.
Project description:Insect cuticle plays essential roles in multiple physiological functions. During molting and metamorphosis, tremendous changes occur in silkworm cuticles. Silkworm is a model of Lepidoptera insects; however, little is known about the stage expression profiles of genes in cuticles of silkworm. In the present study, we selected 16 developmental stages, ranging from day 1 of the first instar larvae to day 8 of pupae, to perform microarray-based expression profiles. The data told us that various functions and physiological pathways were activated in the cuticle. Moreover, the expression profiles of cuticular protein genes, as the important components of cuticle, were investigated. The current study provides important insights for the functional study of insect cuticle and the regulation of insect cuticular protein genes.
Project description:Background: MicroRNA (miRNA) and other small regulatory RNAs contribute to the modulation of a large number of cellular processes. We sequenced three total RNA libraries prepared from the whole body, and the anterior and posterior silk glands of Bombyx mori, with a view to expanding the repertoire of silkworm miRNAs and exploring transcriptional differences in miRNAs between segments of the silk gland. Results: With the aid of large-scale Solexa sequencing technology, we validated 244 unique miRNA genes, including 191 novel and 53 previously reported genes, corresponding to 309 loci in the silkworm genome. Interestingly, 24 unique miRNAs were widely conserved from invertebrates to vertebrates; 12 unique ones were limited to invertebrates and 33 were confined to insects; whereas the majority of the newly identified miRNAs were silkworm-specific. We identified 21 clusters and 42 paralogs of miRNAs in the silkworm genome. However, sequence tags showed that paralogs or clusters are not prerequisites for coordinated transcription and accumulation. The majority of silkworm-specific miRNAs are located in transposable elements, and display significant differences in abundance between the anterior and posterior silk glands. Conclusions: Conservative analysis revealed that miRNAs serve as phylogenetic markers and function in evolutionary signaling. The newly identified miRNAs greatly enriched the repertoire of insect miRNAs, and provide insights into miRNA evolution, biogenesis, and expression in insects. The differential expression of miRNAs in the anterior and posterior silk glands supports their involvement as new layers in the regulation of the silkworm silk gland.
Project description:Uric acid (UA) is the final product of purine metabolism and plays an important role as a physiological antioxidant. In recent years, several different groups have reported a correlation between decreased UA in Parkinson’s disease (PD) and clinical progression and stage of PD. However, little is known about the molecular mechanisms of decreased UA under oxidative stress. We used our systematic functional annotation pipeline for silkworm genes to identify a novel UA metabolic pathway regulator under oxidative stress in a UA metabolism mutant silkworm Bombyx mori model. Gene expression was measured in 3day of fifth instar larvae of abnormal uric acid synthesis Bombyx mori mutant of op.