Characters and expression of the gene encoding DH, PBAN and other FXPRLamide family neuropeptides in Antheraea pernyi

The full-length cDNA encoding diapause hormone (DH) and pheromone biosynthesis activating neuropeptide (PBAN) in Antheraea pernyi (Anp-DH-PBAN) were cloned and sequenced by rapid amplification of cDNA ends methods. The Anp-DH-PBAN cDNA encodes a 196-amino acid (aa) prehormone that contains a 24-aa DH-like peptide, a 33-aa PBAN and three other neuropeptides, all of which share a common C-terminal pentapeptide motif FXPR/KL (X = G, T, S). The Anp-DH-PBAN shows highest homology (82%) to that of Samia cynthia ricini at amino acid level. Northern blots demonstrate the presence of a 0.8-kb transcript in the brain and suboesophageal ganglion (SG) complex. During the early pupal stages, the Anp-DH-PBAN mRNA contents increase consistently in both diapause- and non-diapause-destined pupae. From day 7, mRNA in diapause pupae dropped promptly and maintained a lower level than that in the non-diapause type. The Anp-DH-PBAN mRNA was expressed mainly in SG, at much lower levels in brain and thoracic ganglia (TG), but not in non-neural tissues. FXPRLamide (Phe-X-Pro-Arg-Leu) peptide immunoreactivity was detected in the SG, TG and terminal abdominal ganglion of A. pernyi by whole-mount immunocytochemistry. The titres of FXPRLamide peptides in the haemolymph in diapause type are consistently lower than in non-diapause insects. In non-diapause individuals, there are two peaks of FXPRLamide titres, day 2 in the wandering stage and day-5 in the pupal stage respectively.