Differential expression of sex-related fat body proteins during the larval–pupal developmental stages of the silkworm (Bombyx mori)

Abstract

The silkworm fat body is the site of many intermediary metabolic processes, and a source of sustenance for growth throughout the life cycle. Fat body proteins are responsible for storing nutrients, providing energy, and regulating hormones, and they have been identified using proteomic approaches. However, detailed differential expression of sex-related fat body proteins has not previously been evaluated. In the present study, we characterized the differential expression of sex-related fat body proteins, by using 2-dimensional gel electrophoresis (2-DE) followed by mass spectrometry identification and bioinformatics methods. We extracted the fat body proteins from 5-day-old fifth instar larvae (L5), 10-day-old fifth instar larvae (corresponding to the end of spinning [LE]), and 0-day-old pupae (P0) of the multivoltine silkworm variety “Da Zao”. We confirmed the presence of 11 important sex-specific expression proteins and 14 stage-specific expression proteins. We accurately identified 13 of these specific expression proteins, including actin, calponin-like protein, 75kDa subunit NADH, receptor for activated protein kinase C from Bombyx mori (BmRACK), IMP (inosine monophosphate) cyclohydrolase, tropomyosin 1, β-tubulin, hypothetical protein, antichymotrypsin precursor, and 30K protein precursor. We showed that BmRACK was differentially expressed between male and female silkworms. We discuss the biological roles of the specific expression proteins during the larval–pupal developmental stages.