THE SEQUENCE CHARACTERISTICS OF LPL-A IN COMMON CARP (CYPRINID CARPIO) AND THE EFFECTS OF ITS OVEREXPRESSION ON FAT DEPOSITION

To investigate the effects of overexpressing lipoprotein lipase a gene (lpl-a) in common carp (Cyprinid carpio) on fat deposition patterns and lipid metabolism-related genes expression, we analyzed the sequence and structural characteristics of the carp lpl-a gene and examined its tissue distribution using quantitative real-time (qPCR) in five internal tissues: abdominal fat, liver, kidney, muscle, and intestine. The lpl-a overexpression plasmid vector was constructed by homologous recombination and introduced into zebrafish (Danio rerio) and carp liver cells. The impacts of lpl-a overexpression on total cholesterol (T-CHO), triglyceride (TG) levels, and expressions of lipid metabolism marker genes (pparγ, fabp3, pnpla2, etc.) were assessed in zebrafish (individual level) and carp hepatocytes (cell level). Results showed that the carp lpl-a was predicted to encode a 507-amino acid protein with 7 open reading frames (ORFs), and it demonstrated high evolutionary conservation in osteichthyes. Tissue-specific expression analysis revealed significantly higher lpl-a transcript levels in abdominal fat, liver, and kidney compared to muscle and intestine (P<0.05). In zebrafish, microinjection of the lpl-a overexpression vector resulted in an approximately 7-fold increase in muscle T-CHO and a 1-fold increase in both T-CHO and TG in liver, accompanied by upregulation of lpl-a, ppar γ, and fabp 3 (P<0.05). In carp hepatocytes, transfection with the lpl-a construct for 72h significantly increased lpl-a and lipolytic gene pnpla 2 expressions (P<0.05). Altogether, these findings demonstrate that overexpression of lpl-a induced distinct lipid metabolism regulations at individual (enhanced muscle fat storage and hepatic lipid accumulation) and cellular (activated lipolysis and inhibited lipogenesis) levels, providing theoretical insights for targeting lpl-a to modulate lipid deposition in economically important aquatic animals.