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: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:Human utilization of the mulberry-silkworm interaction started at least 5,000 years ago and greatly influenced world history through the Silk Road. Complementing the silkworm genome sequence, here we describe the genome of a mulberry species (Morus notabilis C. K. Schneider). In the 330 Mb genome assembly of M. notabilis, we identified 128 Mb of repetitive sequences and 29,338 genes, 60.8% of which were supported by transcriptome sequencing. Mulberry gene sequences appear to evolve ~3 times faster than other Rosales, perhaps facilitating its spread to Europe, Africa, and America. It is among few eudicots but several Rosales not preserving genome duplications in more than 100 million years – however neopolyploid series in mulberry and several others suggest that new duplications may confer benefits. Strikingly, five predicted mulberry miRNAs were found in the hemolymph and silkglands of silkworm, suggesting profound molecular level interactions that promise to expand knowledge of plant-herbivore relationship which constitute key elements of most terrestrial habitats. In addition, we investigated the characters of hemolymph small RNA. small mRNA profiles of silkworm hemolymph in the fifth instar day-5 silkworm were generated by deep sequencing, in twice, using Illumina Hiseq 2000.
Project description:As important roles of small RNA pathways, AGO proteins mediate interaction of incorporated small RNAs with their targets. The resolution of AGO associated small RNAs showed a significant landscape of AGO proteins and their binding small RNAs. To characterize small RNAs that associated with BmAGO2 protein in Bombyx mori, the small RNA population associated with BmAGO2 in BmN cells was extracted from the AGO immunoprecipitated complex and the small RNAs between 17nt to 50nt separated by a polyacrylamide gel electrophoresis were subjected to library construction and deep sequencing.The high throughput sequencing yielded a total of 11691441 reads, representing 813,702 unique reads with a abundance from 5731905 to 1.
Project description:As important roles of small RNA pathways, AGO proteins mediate interaction of incorporated small RNAs with their targets. The resolution of AGO associated small RNAs showed a significant landscape of AGO proteins and their binding small RNAs. To characterize small RNAs that associated with BmAGO2 protein in Bombyx mori, the small RNA population associated with BmAGO2 in BmN cells was extracted from the AGO immunoprecipitated complex and the small RNAs between 17nt to 50nt separated by a polyacrylamide gel electrophoresis were subjected to library construction and deep sequencing.The high throughput sequencing yielded a total of 11691441 reads, representing 813,702 unique reads with a abundance from 5731905 to 1. Small RNA associated with AGO2 of BmN cell infected with ie1-bacmid recombinant viruses were performed by high-throughput using Hiseq 2000.
Project description:Maternal genes present in mature oocytes and play a crucial role in the early development of the silkworm. Although maternal genes have been widely studied in many species, there are limited research in Bombyx mori. High-through experimental technology provides a practical way for genome-wide study. Here we show a transcriptome study on silkworm eggs. Unfertilized eggs from five different stages of early development were used for detecting the change situation of gene expression. The expressed genes showed different patterns over time. Maternal genes were annotated according to homology analysis with Drosophila melanogaster. In our result, more than a half expressed maternal genes were fall into four expression patterns and showed downward trend over time. The function annotation of material genes showed that they were related to transcription factor activity, growth factor activity, nucleic acid binding, RNA binding, ATP binding, ion binding and so on. In additional, twenty-two gene clusters including material genes were identified from 18 scaffolds. Altogether, we plotted a profile for maternal genes of Bombyx mori using digital gene expression profiling method. It will provide a base for mother-specific signature research and improve the understanding of early development of silkworm.
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.