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Transcriptomic analysis of differentially expressed genes in the Ras1(CA)-overexpressed and wildtype posterior silk
1Key Laboratory of Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China. cheng.leilei@zs-hospital.sh.cn.
BMC Genomics
|March 11, 2014
Summary
Overexpressing Ras1(CA) in silkworms boosts silk yield by activating MAPK and PI3K-TORC1 pathways, leading to increased cell growth and gene expression in metabolism and cell cycle pathways.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Previous studies utilized the Bombyx mori GAL4/UAS system to show Ras1(CA) oncogene overexpression in the posterior silk gland (PSG) enhances cell growth, fibroin synthesis, and silk yield.
- The precise molecular mechanisms underlying these improvements require further investigation.
Purpose of the Study:
- To elucidate the molecular mechanisms by which Ras1(CA) overexpression in the silkworm posterior silk gland influences gene expression and silk production.
- To compare transcriptomes between Ras1(CA)-overexpressed and wildtype posterior silk glands using Illumina sequencing.
Main Methods:
- Whole-transcriptome sequencing (Illumina) was performed on posterior silk glands from Ras1(CA)-overexpressed and wildtype silkworms.
- Differential gene expression analysis was conducted using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations.
- Quantitative real-time PCR (qPCR) was used to validate transcriptional changes.
- Functional analysis involved injecting small-molecule inhibitors of Ras1 downstream effectors.
Main Results:
- Transcriptomic analysis identified thousands of differentially expressed genes (DEGs) in Ras1(CA)-overexpressed PSGs.
- Upregulated DEGs were significantly enriched in cancer pathways, insulin signaling, MAPK signaling, purine metabolism, and pyrimidine metabolism.
- Inhibition studies confirmed the requirement of both Raf-MAPK and PI3K-TORC1 pathways for Ras1-induced gene expression changes.
Conclusions:
- Ras1(CA) activates its downstream Raf-MAPK and PI3K-TORC1 pathways at the transcriptional level, in addition to phosphorylational regulation.
- Ras1(CA) promotes increased DNA content and endoreplication by upregulating genes involved in nucleotide metabolism and the cell cycle.
- These findings provide a deeper understanding of the molecular basis for enhanced silk yield due to Ras1(CA) overexpression in the posterior silk gland.
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