Regulation of progastricsin mRNA levels in sea bass (Dicentrarchus labrax) in response to fluctuations in food availability

In this study the sea bass (Dicentrarchus labrax) pepsinogen C gene was isolated. The nucleotide sequences of all exons are presented.
The organization of the gene is compatible with that of other aspartic proteinases. The predicted 388-residue amino acid (aa) sequence of
sea bass pepsinogen C consists of a signal sequence of 16 amino acid residues, an activation peptide of 43 residues, and the mature pepsin
of 329 residues containing the two characteristic active-site aspartic acids. We also analyzed fasting-induced changes in the expression of
progastricsin mRNA, using real-time RT-PCR absolute quantification. Progastricsin mRNA copy number was downregulated under
conditions of negative energy balance, such as starvation, and upregulated during positive energy balance, such as refeeding. These findings
offer new information about the sea bass progastricsin gene and support a role of this gastric digestive enzyme in the regulation of
food intake in sea bass.