Time-course transcriptome data of silk glands in day 0-7 last-instar larvae of Bombyx mori (w1 pnd strain).

Time-course transcriptome expression data were constructed for four parts of the silk gland (anterior, middle, and posterior parts of the middle silk gland, along with the posterior silk gland) in the domestic silkworm, Bombyx mori, from days 0 to 7 of the last-instar larvae. For sample preparation, silk glands were extracted from one female and one male larva every 24 hours accurately after the fourth ecdysis. The reliability of these transcriptome data was confirmed by comparing the transcripts per million (TPM) values of the silk gene and quantitative reverse transcription PCR results.

Efficient RNA interference method during caste differentiation with hormone treatment in the termite (Isoptera: Rhinotermitidae).

Unveiling the proximate mechanism of caste differentiation is crucial for understanding insect social evolution, and gene function analysis is an important tool in this endeavor. The RNA interference (RNAi) technique is useful in termites, but its knockdown effects may differ among species. One of the most important model species in the field of termite sociogenomics is Kolbe (Isoptera: Rhinotermitidae).

Comparison of gene expression profiles among caste differentiations in the termite Reticulitermes speratus.

Termite castes express specialized phenotypes for their own tasks and are a good example of insect polyphenism. To understand the comprehensive gene expression profiles during caste differentiation, RNA-seq analysis based on the genome data was performed during the worker, presoldier, and nymphoid molts in Reticulitermes speratus. In this species, artificial induction methods for each molt have already been established, and the time scale has been clarified.

Evolution and functionalization of vitellogenin genes in the termite Reticulitermes speratus.

Eusociality has been commonly observed in distinct animal lineages. The reproductive division of labor is a particular feature, achieved by the coordination between fertile and sterile castes within the same nest. The sociogenomic approach in social hymenopteran insects indicates that vitellogenin (Vg) has undergone neo-functionalization in sterile castes.

Co-Expression Network and Time-Course Expression Analyses to Identify Silk Protein Regulatory Factors in .

is an important economic insect and an animal model in pharmacomedical research. Although its physiology has been studied for many years, the mechanism via which silk protein genes are regulated remains unclear. In this study, we performed two-step expression screening, namely co-expression network and time-course expression analyses to screen silk protein regulation factors.

Evolutionary transition of doublesex regulation from sex-specific splicing to male-specific transcription in termites.

The sex determination gene doublesex (dsx) encodes a transcription factor with two domains, oligomerization domain 1 (OD1) and OD2, and is present throughout insects. Sex-specific Dsx splicing isoforms regulate the transcription of target genes and trigger sex differentiation in all Holometabola examined to date. However, in some hemimetabolous insects, dsx is not spliced sexually and its sequence is less conserved.

Reproductive Soldier Development Is Controlled by Direct Physical Interactions with Reproductive and Soldier Termites.

In eusocial insects (e.g., ants, bees, and termites), the roles of different castes are assigned to different individuals.

A Crucial Caste Regulation Gene Detected by Comparing Termites and Sister Group Cockroaches.

Sterile castes are a defining criterion of eusociality; investigating their evolutionary origins can critically advance theory. In termites, the soldier caste is regarded as the first acquired permanently sterile caste. Previous studies showed that juvenile hormone (JH) is the primary factor inducing soldier differentiation, and treatment of workers with artificial JH can generate presoldier differentiation.

TGFβ signaling related genes are involved in hormonal mediation during termite soldier differentiation.

A working knowledge of the proximate factors intrinsic to sterile caste differentiation is necessary to understand the evolution of eusocial insects. Genomic and transcriptomic analyses in social hymenopteran insects have resulted in the hypothesis that sterile castes are generated by the novel function of co-opted or recruited universal gene networks found in solitary ancestors. However, transcriptome analysis during caste differentiation has not been tested in termites, and evolutionary processes associated with acquiring the caste are still unknown.

Ecdysone signaling regulates soldier-specific cuticular pigmentation in the termite Zootermopsis nevadensis.

Termite caste differentiation requires hormonal regulation, but understanding of the role of ecdysone is limited. Here, we investigated the expression and function of ecdysone-related genes during soldier differentiation in the damp-wood termite Zootermopsis nevadensis. Ecdysone receptor gene (EcR) was highly expressed in the head just after the presoldier molt.

Gene expression changes in the tyrosine metabolic pathway regulate caste-specific cuticular pigmentation of termites.

In social insects, all castes have characteristic phenotypes suitable for their own tasks and to engage in social behavior. The acquisition of caste-specific phenotypes was a key event in the course of social insect evolution. However, understanding of the genetic basis and the developmental mechanisms that produce these phenotypes is still very limited.

Knockdown of the juvenile hormone receptor gene inhibits soldier-specific morphogenesis in the damp-wood termite Zootermopsis nevadensis (Isoptera: Archotermopsidae).

The Methoprene-tolerant (Met) protein has been established as a juvenile hormone (JH) receptor. Knockdown of the Met gene caused precocious metamorphosis and suppression of ovarian development. However, the function of Met in caste development of social insects is unclear.

High Laccase2 expression is likely involved in the formation of specific cuticular structures during soldier differentiation of the termite Reticulitermes speratus.

Termite soldiers are morphologically specialized for colony defense. Analysis of the mechanisms of soldier differentiation is important for understanding the establishment of termite societies. Soldiers differentiate from workers through a presoldier stage and have well-sclerotized and pigmented cuticles.