Cloning, tissue expression profiling, functional characterization of corticotropin-releasing hormone (crh) on feeding in gibel carp (Carassius auratus gibelio)

Abstract:

To elaborate the mechanism of corticotropin-releasing hormone (crh) on feeding in gibel carp (Carassius auratus gibelio), we cloned and identified the full-length cDNA sequence of crh for the first time. We also employed real-time quantitative PCR (RT-PCR) to explored crh mRNAon distribution in different tissues and investigated the expression of crh mRNA during postprandial and fasting. Here, a 920 bp full-length of crh gene cDNA was obtained, including a 53 bp of 5-UTR, a 378 bp of 3-UTR, and a 489 bp of an open reading frame (ORF). The ORF of the gibel carp crh gene contains 162 bp nucleotides, including an 11-amino acid conserved region, a 24-amino acid signal peptide, and a 41-amino acid mature peptide. The amino acid sequence of crh shares a high level of similarity with teleost CRH (99% with Carassius auratus and 96% with Cyprinus carpio). The expression of gibel carp crh was observed in almost all tissues, with the highest expression detected in the hypothalamus, followed by the myelencephalon and heart. There was no significant change in crh gene expression in the fed group compared with the fasted group in gibel carp hypothalamus after a meal (P>0.05). However, the expression level of the crh gene showed a significant decrease after fasting on day 5 and day 7 (P<0.01), a significant increase of the crh gene was observed after refeeding on day 9 and day 11. The results suggest that the crh gene may play a critical role in feeding regulation in gibel carp.