Genome-wide identification, phylogeny and expression analysis of G6PC gene family in common carp, Cyprinus carpio

Objective: The Glucose 6-phosphatase (G6Pase) catalytic subunit (G6PC) catalyzes glucose 6-phosphate (G6P) to inorganic phosphate and glucose, playing a critical role in endogenous energy supply. Here, the G6PC gene family was investigated and characterized in common carp (Cyprinus carpio). Methods: Sequence alignment and phylogenetic analysis were performed using MEGA5. The HMM profiles, motif structure were analyzed using Pfam and MEME, respectively. Quantitative real-time PCR was used to test the expression profiles. Results: Four assumptive members of G6PC family in common carp whole-genome sequence were identified as cg6pca.1, cg6pca2a, cg6pca.2b and cg6pcb which were classified into g6pca and g6pcb subtypes, respectively. Evolutionary analysis revealed that cg6pca.2a and cg6pca2b have a closer evolutionary relationship, and the same subtype members have higher homology among different species. A classical PAP2-glucose phosphates domain is found in four genes and were highly conserved. The expression patterns revealed that only cg6pca.2a elevated significantly after 12 and 24 h of both starvation and cold treatment (p <0.05). Conclusions: This study performed a comprehensive analysis of G6PC gene family in common carp. Moreover, cg6pca2 may be the major functional gene in cold and fasting stress. And the transfactors, PLAG1 and Sox8, may be concerned with expression regulation of cg6pca.2.