IP Endocrinology

Molecular cloning of a prothoracicostatic peptide (PTSP) in the larval brain of the silkworm, Bombyx mori

Y.-J. Hua 1,2 , Y. Tanaka 2 & H.Kataoka 3

1 Inst. Nuclear-Agricult. Sci., Zhejiang Univ., 310029 Hangzhou, China; 2 Lab of Bioactive Substances, Natl. Inst. of Seircul. & Entomol. Sci., 305-8634 Tsukuba, Japan; 3 Dept. of Intergrated Biosci., Graduate School of Frotier Sci., Tokyo Univ. 113-0032 Tokyo, Japan

Ecdysone secreted by the prothoracic gland (PG) plays a central role in the insect metamorphosis as molting hormone, which biosynthesis is considered to be stimulated by prothoracicotropic hormone (PTTH). Recently, we have identified a prothoracicostatic peptide (PTSP) from the brain of the silkworm, Bombyx mori. PTSP strongly inhibited ecdysteroidogenesis in the PGs of spinning larvae, and simultaneous application of PTSP and PTTH to the PGs of the feeding larvae inhibited the PTTH-stimulated ecdysteroidogenesis. These results indicate the importance of PTSP in the regulation of ecdysteroidogenesis. Using RT-PCR and 5’-RACE we have cloned PTSP cDNA from B. mori brain. The predicted open reading frame encoded 288 amino acids including five repeats of PTSP and five other structure-related peptides. Some related peptides also showed prothoracicostatic activity in the in vitro bioassay. Northern blot analysis indicated that PTSP gene is expressed mainly in the brain.

Index terms: Bombyx mori, ecdysteroidogenesis, prothoracicostatic peptide, cDNA

Copyright: The copyrights of this original work belong to the authors (see right-most box in title table). This abstract appeared in Session 19 – SOCIAL INSECTS AND SERICULTURE Symposium and Poster Session, ABSTRACT BOOK II – XXI-International Congress of Entomology, Brazil, August 20-26, 2000.