Molecular Characterization of PGC-1ß (PPAR Gamma Coactivator 1ß) and its Roles in Mitochondrial Biogenesis in Blunt Snout Bream (Megalobrama amblycephala).

ABSTRACT

This study aimed at achieving the molecular characterization of peroxisome proliferator-activated receptor-gamma coactivator 1ß (PGC-1ß) and exploring its modulatory roles in mitochondria biogenesis in blunt snout bream (Megalobrama amblycephala). A full-length cDNA of PGC-1ß was cloned from liver which covered 3110 bp encoding 859 amino acids. The conserved motifs of PGC-1ß family proteins were gained by MEME software, and the phylogenetic analyses showed motif loss and rearrangement of PGC-1ß in fish. The function of PGC-1ß was evaluated through overexpression and knockdown of PGC-1ß in primary hepatocytes of blunt snout bream. We observed overexpression of PGC-1ß along with enhanced mitochondrial transcription factor A (TFAM) expression and mtDNA copies in hepatocytes, and its knockdown led to slightly reduced NRF1 expression. However, knockdown of PGC-1ß did not significantly influence TFAM expression or mtDNA copies. The alterations in mitochondria biogenesis were assessed following high-fat intake, and the results showed that it induces downregulation of PGC-1ß. Furthermore, significant decreases in mitochondrial respiratory chain activities and mitochondria biogenesis were observed by high-fat intake. Our findings demonstrated that overexpression of PGC-1ß induces the enhancement of TFAM expression and mtDNA amount but not NRF-1. Therefore, it could be concluded that PGC-1ß is involved in mitochondrial biogenesis in blunt snout bream but not through PGC-1ß/NRF-1 pathway.