Cuticular protein genes in Tenebrio molitor (Coleoptera: Tenebrionidae)

We have previously isolated from the beetle Tenebrio molitor, cDNAs coding for two glycine-rich cuticular proteins named ACP-20, ACP-22 and ACP-17 and an alanin-rich cuticular protein named LPCP-22. The ACP-20, ACP-22, ACP-17 mRNAs are detected by Northern blot and in situ hybridization analysis only in epidermal regions secreting heavily sclerotized cuticle during the pharate adult stage. The LPCP-22 mRNA is detected in most epidermal regions during the secretion of larval and pupal cuticles. Then, its presence is restricted to the epidermal zones secreting intersegmental soft cuticle in the newly ecdysed pupa. This stage- and tissue-specific gene system seems to be a convenient model for studying the regulation of sequential gene expression by ecdysteroids and juvenile hormone.