Project description:3 day of fifth instar larvae were treated with ultra-violet (UV) rays using UVL-56 (1350?W/cm2, UVP) for 6 and 12 hours (29.2 and 58.32 J/cm2). Since, larvae of each group rare on artificial diet for 24 hour and dissected fatbody. We examined gene expression profile in these groups. Gene expression was measured in 3 day of fifth instar larvae of ultra violet irradiation.
Project description:To identify functions that distinguish the posterior and median cells producing fibroin and sericin in the silk gland of Bombyx mori, serial analysis of gene expression (SAGE) profiles from both silk gland regions were analyzed and compared. The construction of a B. mori reference tag collection extracted from a set of 38000 Bombyx EST sequenced from the 3’ side, helped annotating the SAGE libraries. Most of the tags appeared at similar relative concentration in the two libraries except for those corresponding to silk proteins that were found region-specific and highly abundant. Strikingly, besides tags from silk protein mRNAs, 19 tags were found in the class of high abundance in the median cell library, which were absent in the posterior cell tag collection. Except tags from SP1 mRNA, no PSG specific tags were found in the same class of abundance. The analysis of MSG-specific different transcripts led to suggest that middle silk gland cell realizes more diversified functions as those already known, of synthesis and secretion of the silk sericins.
Project description:Background: The growth and development of the posterior silk gland and the biosynthesis of the silk core protein at the fifth larval instar stage of Bombyx mori are of paramount importance for silk production. Results: Here, aided by next-generation sequencing and microarry assay, we profile 1,229 microRNAs (miRNAs), including 728 novel miRNAs and 110 miRNA/miRNA* duplexes, from the posterior silk gland at the fifth larval instar. Target gene prediction yields 14,222 unique target genes from 1,195 miRNAs. Functional categorization classifies the genes into complex pathways that include both cellular and metabolic processes, especially protein synthesis and processing. Conclusion: The enrichment of target genes in the ribosome-related pathway indicates that miRNAs may directly regulate translation. Our findings pave a way for further functional elucidation of these miRNAs in silk production.
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:3 day of fifth instar larvae were treated with ultra-violet (UV) rays using UVL-56 (1350μW/cm2, UVP) for 6 and 12 hours (29.2 and 58.32 J/cm2). Since, larvae of each group rare on artificial diet for 24 hour and dissected fatbody. We examined gene expression profile in these groups.