Gene encoding the prothoracicotropic hormone of a moth is expressed in the brain and gut.
The molts of lepidopteran insects are typically controlled by the brain-derived prothoracicotropic hormone (PTTH) that stimulates ecdysteroidogenesis in the prothoracic glands (PGs). We report here that the larvae and pupae of the moth Sesamia nonagrioides can molt without brain (PGs must be present), suggesting that there might be a secondary source of PTTH. We addressed this issue by characterizing spatial and temporal expression patterns of the PTTH gene. To this end we identified a major part of the corresponding cDNA. Protein deduced from this cDNA fragment consisted of 128 amino acids and showed 48-85% homology with the matching regions of PTTHs known from other Lepidoptera. Quantification of PTTH expression in major body organs of the last instar larvae revealed high expression in the brain (fading in post-feeding larvae) and considerable expression in the gut (with a maximum in post-feeding larvae). The content of PTTH message in the gut was enhanced after decapitation. It is concluded that the molts of S. nonagrioides larvae are driven by PTTH gene expression in the gut.
Pérez-Hedo
Meritxell
M
Centre R+D de Lleida (Udl-IRTA), Rovira Roure 191, 25198 Lleida, Spain.
Pena
Ramona N
RN
Sehnal
František
F
Eizaguirre
Matilde
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000378:metabolism*; D015870:Gene Expression; D007301:Insect Hormones / Q000096:biosynthesis / Q000235:genetics*; D007814:Larva / Q000378:metabolism; D007915:Lepidoptera / Q000235:genetics; D008969:Molecular Sequence Data; D018978:Molting / Q000235:genetics*; D009036:Moths / Q000235:genetics*; D011679:Pupa / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D007301:Insect Hormones; C009089:prothoracicotropic hormone