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Molecular Characterization of Prothoracicotropic Hormone (PTTH) from the Giant SilkmothAntheraea pernyi:Developmental Appearance of PTTH-Expressing Cells and Relationship to Circadian Clock Cells in Central Brain

Harvard University, Cambridge, Massachusetts, United States
Developmental Biology (Impact Factor: 3.64). 10/1996; 178(2):418-29. DOI: 10.1006/dbio.1996.0228
Source: PubMed

ABSTRACT Using a PCR strategy, we have cloned the cDNA for prothoracicotropic hormone (PTTH) from the giant silkmoth, Antheraea pernyi. The A. pernyi PTTH cDNA encodes a preprohormone of 221 amino acids that is 51 and 71% identical at the amino acid level with Bombyx mori and Samia cynthia ricini PTTHs, respectively. Bacterially expressed, recombinant A. pernyi PTTH stimulates adult development when injected into debrained pupae. PTTH protein (ca. 30 kDa by Western blot) and mRNA (ca. 0.9 kb by Northern blot) are expressed in brain. Immunocytochemistry and in situ hybridization show that PTTH protein and mRNA are colocalized in L-NSC III from Day 4 of embryogenesis through adult life, with little variation in either protein or mRNA levels at the various ecdyses. A pair of cells expressing immunoreactivity for the circadian clock protein PER is located in the same region as PTTH-expressing L-NSC III in A. pernyi brain. However, double-label immunocytochemical studies show that PTTH and PER are located in different cells. The close anatomical location between PTTH- and PER-expressing cells suggests routes of communication between these two cell populations that may be important for the circadian control of PTTH release.

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    • "PTTH was first purified from the silkworm B. mori as a 30-kDa peptide, consisting of two identical subunits linked with a disulfide bond (Kawakami et al., 1990; Kataoka et al., 1991). Until now PTTH has been identified in Samia cynthia ricini (Ishizaki and Suzuki, 1994), Antheraea pernyi (Sauman and Reppert, 1996), Hylophora cecropia (Sehnal et al., 2002), Manduca sexta (Shionoya et al., 2003), and Helicoverpa zea (Xu et al., 2003). In Lymantria dispar caterpillars this neurohormone was identified by Kelly et al. (1991) and its molecular mass was determined as 11–15 kDa. "
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    • "Sequence alignment indicates huge variation in PTTH at the primary structure level, suggesting that the PTTH molecule evolved rapidly from a common ancestral gene. Following the first report on the cDNA structure of PTTH in B. mori (Kawakami et al., 1990), the structures of quite a few PTTH cDNAs have been described, including Samia cynthia (Ishizaki & Suzuki, 1994), Antheraea pernyi (Sauman & Reppert, 1996), Hyalophora cecropia (Sehnal et al., 2002), Manduca sexta (Shionoya et al., 2003), and several noctuids including Heliothis virescens (Xu & Denlinger, 2003), Helicoverpa zea (Xu et al., 2003), Helicoverpa armigera (Wei et al., 2005), and Spodoptera exigua (Xu et al., 2007). These PTTHs are exclusively from Lepidoptera. "
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