MOLECULAR CHARACTERIZATION OF PROTHORACICOTROPIC HORMONE (PTTH) FROM THE GIANT SILKMOTH ANTHERAEA-PERNYI - DEVELOPMENTAL APPEARANCE OF PTTH-EXPRESSING CELLS AND RELATIONSHIP TO CIRCADIAN CLOCK CELLS IN CENTRALBRAIN

Using a PCR strategy, we have cloned the cDNA for prothoracicatropic h ormone (PTTH) from the giant silkmoth, Antheraea pernyi. The A, pernyi PITH cDNA encodes a preprohormone of 221 amino acids that is 51 and 7 1% identical at the amino acid level with Bombyx mori and Samia cynthi a ricini PTTHs, respectively. Bacterially expressed, recombinant A. pe rnyi PTTH stimulates adult development when injected into debrained pu pae. PTTH protein (ca, 30 kDa by Western blot) and mRNA (ca. 0.9 kb by Northern blot) are expressed in brain. Immunocytochemistry and in sit u hybridization show that PTTH protein and mRNA are colocalized in L-N SC III from Day 4 of embryogenesis through adult life, with little var iation in either protein or mRNA levels at the various ecdyses. A pair of cells expressing immunoreactivity for the circadian flock protein PER is located in the same region as PTTH-expressing L-NSC III in A. p ernyi brain. However, double-label immunocytochemical studies show tha t PTTH and PER are located in different cells. The close anatomical lo cation between PTTH- and PER-expressing cells suggests routes of commu nication between these two cell populations that map be important for the circadian control of PTTH release. (C) 1996 Academic Press, Inc.