The Pitx homeobox gene in Bombyx mori: Regulation of DH-PBAN neuropeptide hormone gene expression

• Published in: Molecular and cellular neuroscience Vol. 34; no. 2; pp. 209 - 218
• Main Authors: Shiomi, Kunihiro, Fujiwara, Yoshihiro, Yasukochi, Yuji, Kajiura, Zenta, Nakagaki, Masao, Yaginuma, Toshinobu
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.2007
• Subjects: Animals; Baculovirus; Bicoid-like homeobox; Bombyx - genetics; Bombyx mori; Cloning, Molecular; DH-PBAN; Diapause; Diapause hormone; Gene Expression Regulation - physiology; Genes, Homeobox - physiology; Green Fluorescent Proteins - metabolism; Insect; Insect Proteins - metabolism; Larva; Molecular Sequence Data; Neuropeptide hormone; Neuropeptides - metabolism; Neurosecretory cells; Pitx; Protein Precursors - metabolism; Reverse Transcriptase Polymerase Chain Reaction - methods; RNA Interference - physiology; CC; Diapause hormone; GH; Bicoid-like homeobox; DH; Diapause; Neurosecretory cells; Bombyx mori; PRL; EGFP; DH-PBAN; Baculovirus; BmPitx; Neuropeptide hormone; AcNPV; POMC; SG; RT-PCR; LHβ; Pitx; PBAN; DHPCs; Insect; CA
• ISSN: 1044-7431; 1095-9327
• DOI: 10.1016/j.mcn.2006.10.015

The diapause hormone–pheromone biosynthesis activating neuropeptide gene, DH-PBAN, is expressed exclusively in seven pairs of DH-PBAN-producing neurosecretory cells (DHPCs) on the terminally differentiated processes of the subesophageal ganglion (SG). To help reveal the regulatory mechanisms of cell-specific DH-PBAN expression, we identified a cis-regulatory element that regulates expression in DHPCs using the recombinant AcNPV-mediated gene transfer system and a gel-mobility shift assay. Bombyx mori Pitx (BmPitx), a bicoid-like homeobox transcription factor, binds this element and activates DH-PBAN expression. The BmPitx was expressed in various tissues, including DHPCs in the SG. Suppression of DH-PBAN expression by silencing of the BmPitx successfully induced non-diapaused eggs from a diapause egg producer. To the best of our knowledge, this report is the first to identify a neuropeptide-encoding gene as a target of the Pitx transcriptional regulator in invertebrates. Thus, it is tempting to speculate that functional conservation of Pitx family members on neuropeptide gene expression occurs through a “combinational code mechanism” in both vertebrate and invertebrate in neuroendocrine systems.