Identification and characterization of a novel corticotropin-releasing hormone-binding protein (CRH-BP) gene from Chinese honeybee (Apis cerana cerana).

Corticotropin-releasing hormone-binding protein (CRH-BP) is an essential secreted glycoprotein for coordinating the neuroendocrine responses to stress by binding either CRHs or its related peptides. A novel CRH-BP gene AccCRH-BP from Apis cerana cerana was identified and characterized. Its genomic DNA was consisted of seven exons and six introns, and shared high similarity with the homologous members from other insects and vertebrates. Homologous and phylogenetic analysis indicated that AccCRH-BP was highly conserved, suggesting the maintenance of conservative structure might be necessary for its biological function. Real-time quantitative PCR revealed that AccCRH-BP was highly expressed in pupa and adult, especially in the head of pupa. However, there was no expression in larval stage. Furthermore, the transcripts of AccCRH-BP in the brain of honeybees were induced by exposure to environmental stresses including UV-light, heat, and cold. The expression level of AccCRH-BP in workers or queens was significantly higher than that of drones. Additionally, analysis of 5'-flanking region of AccCRH-BP revealed a number of putative development and stress transcription factor-binding sites. These data suggest that AccCRH-BP may play important roles in the regulation of honeybee development, and in the central nervous system of the brain to regulate the neuroendocrine stress responses.