Expression profile of cuticular genes of silkworm, Bombyx mori

Abstract

BackgroundInsect cuticle plays essential roles in many physiological functions. During molting and metamorphosis tremendous changes occur in silkworm cuticle where multiple proteins exist and genes encoding them constitute about 1.5% of all Bombyx mori genes.ResultsIn an effort to determine their expression profiles, a microarray-based investigation was carried out using mRNA collected from larvae to pupae. The results showed that a total of 6676 genes involved in various functions and physiological pathways were activated. The vast majority (93%) of cuticular protein genes were expressed in selected stages with varying expression patterns. There was no correlation between expression patterns and the presence of conserved motifs. Twenty-six RR genes distributed in chromosome 22 were co-expressed at the larval and wandering stages. The 2 kb upstream regions of these genes were further analyzed and three putative elements were identified.ConclusionsData from the present study provide, for the first time, a comprehensive expression profile of genes in silkworm epidermal tissues and evidence that putative elements exist to allow massive production of mRNAs from specific cuticular protein genes.

Annotation and expression analysis of cuticular proteins from the tobacco hornworm, Manduca sexta

“…Remarkably, three of the genes belonged to the Tweedle family (of which only four were found in M. sexta ) and the other three are CPR RR-2 genes that are clustered together in the genome. Similar observations were reported for B. mori in that CPT2-4 shared the same expression pattern with the highest expression occurring at the larval stage during the molt (Liang et al, 2010). …”

“…This represents the largest number of CPR genes in any insect genome annotated to date and is 36% greater than the number of CPR genes in the silkworm B. mori : 56 RR-1, 93 RR-2, and 4 RR-3; 149 were originally annotated by Futahashi et al (2008) including the misclassified CPH5, three more were added by Liang et al (2010), and one additional gene, LOC101743422, was discovered in our analysis. Similar to observations for other insects (Cornman et al ., 2008; Dittmer et al ., 2012; Gallot et al ., 2010; Liang et al ., 2010), many of the genes occurred in clusters: 55 of the RR-1 genes were found in clusters of 11-17 genes on four scaffolds (00081, 00136, 00224, 00529), while 86 of the RR-2 genes were found in clusters of 8-26 genes on six scaffolds (00006, 00227, 00685, 00717, 01004, 01013) (Table 1). …”

“…Combining proteomics with genomics has been used to identify cuticular proteins for several insect species (Bae et al ., 2011; Carrasco et al ., 2011; Dittmer et al ., 2012; Fu et al ., 2011; He et al ., 2007). Similarly, genomics and transcriptomics have contributed valuable information on CP gene expression, discerning variations in the timing (pre- or post-molt), developmental stage (larval, pupal, adult), and relative expression levels of these genes (Cornman and Willis, 2009; Dittmer et al ., 2012; Futahashi et al ., 2008; Gallot et al ., 2010; Liang et al ., 2010; Okamoto et al ., 2008; Suetsugu et al ., 2013; Togawa et al ., 2007, 2008). …”

RNAi Trigger Delivery into <em>Anopheles gambiae</em> Pupae

“…In many insect species, including An. gambiae, genes involved in processes such as development (i.e., pupal cuticular and chitin-binding proteins) [27][28][29][30][31] and immune response (i.e., Toll receptor-like proteins) 27,[32][33][34] are highly expressed during the pupal stage. Once a fully formed adult has emerged, there is continued gene expression in response to environmental and physiological changes , as well as other key genes (i.e., sperm specific protein and cytochrome P450 metabolism enzymes) 27,36 .…”

Transcription Profiling Associated With Life Cycle of Anopheles gambiae

“…These include seven genes encoding the cuticular proteins (AGAP002994, AGAP003384, AGAP003390, AGAP005969, AGAP006149, AGAP012462, and AGAP012466) and two genes involved in cytoskeleton structures (AGAP001315, AGAP001678). This noticeable pattern of high induction of the genes encoding cytoskeletons and cuticle proteins is also observed in many different insect pupae (Dotson et al 1998, Hopkins et al 2000, Liang et al 2010. In Drosophila and other dipteran insects, most epidermis of pupae is derived from imaginal discs, and the broad gene is expressed in the epidermis during the pupal formation, but not during adult differentiation (Zhou and Riddiford 2002).…”