Localization of a cuticular protein during the postembryonal development of Manduca sexta

The pattern of cuticle protein synthesis by the epidermis of insects change s during the last larval, pupal and adult development, leading to an altera tion in cuticular stucture and feature. We have isolated a protein that had an apparent molecular mass of 33.1 kD from larval cuticle of Manduca sexta . Synthesis, transport and accumulation of MsCP33.1 were followed during me tamorphosis by immunoblots and immunocytochemical methods using the antibod y developed against this protein. Our data prove that the presence of MsCP3 3.1 in the larval cuticle is general while its appearance in the pupal or a dult integument is restricted only in the cuticle of wings and apodemes. We established that the synthesis of 33.1 kD protein is negatively regulated by moulting hormone (20-hydroxyecdysone). Possible roles for this cuticular protein are discussed.