Estudo da expressão do gene da proteína ligadora de acil-coenzima A no inseto Tribolium castaneum

Abstract

Acil-CoA binding proteins (ACBP) act to regulate the availability of lipids in the intracellular region for the various cellular metabolic processes, and constitute a highly conserved family. Therefore, their functions can be associated with one or more basic processes common to all cells. However, its precise role in lipid metabolism is not yet fully understood. Therefore, the objective of this work is to identify the acyl-CoAs binding proteins (ACBPs) of the insect Tribolium castaneum through the characterization of gene expression, especially the gene called TcACBP6. After identifying the genes coding for ACBP in this insect, the expression analysis was performed in the developmental stages and tissues of the insects by RT-qPCR. To investigate the function of the TcACBP6 gene, silencing was performed, which occurred from the injection of 0.15μg of specific dsRNA for TcACBP6 in larvae. The effect was evaluated by measuring the content of triacylglycerols, analysis of fatty bodies by confocal microscopy and measurement of beta-oxidation. The larvae were also submitted to a high fat diet with 15% olive oil in the base diet and separately, 10% tetrahydrolipstatin (orlistate®), a pancreatic lipase inhibitor drug, also associated with the base diet, being analyzed in isolated groups. The effect was verified in the analysis of gene expression and content of triacylglycerol after 4 days of treatment. From the results for the expression of the TcACBPs genes, greater relative expression was observed in the adult insect and in the larva, although the gene has been expressed in all stages of development. Larvae silenced for TcACBP6 showed inhibition of expression by 87%, which caused an effective reduction in beta oxidation and the formation of a different pattern of lipid droplets in the fatty body, however, there was no increase in the content of triacylglycerols. In the treatment with high fat content, there was a high accumulation of triacylglycerol and this was associated with reduced expression of TcACBP6. However, an opposite effect was observed in larvae treated with tetrahydrolipstatin. Thus, it is concluded that there is a relative expression of this gene at the moment of the transition from the larva to adulthood, considering an important function probably in the mobilization of fatty acids for beta-oxidation.