Drosophila as a genetic model for studying lipid storage droplet-associated genes

脂肪滴関連遺伝子研究のための遺伝モデルとしてのショウジョウバエ

2016-09-26

2016-09-26

Although triacylglycerol, the major component for lipid storage, is essential for normal physiology, its excessive accumulation causes obesity in adipose tissue and is associated with organ dysfunction in non-adipose tissue. Here, we used Drosophila as a model for study the function of genes localized on surface of lipid droplets. In Drosophila melanogaster, the brummer (bmm) gene related to the regulation of lipid storage is homologous with human adipocyte triglyceride lipase, while perilipins are evolutionarily conserved from Drosophila to humans, the Lipid storage droplet 1 (Lsd1) is a Drosophila homolog of human perilipin 1. In the present study, we established a Drosophila model for monitoring bmm expression by using the green fluorescent protein (GFP) gene as a downstream reporter of the bmm promoter. The third instar larvae of Drosophila showed the GFP signal in all tissues observed and specifically in the salivary gland nucleus. Analyzing glucose diets on bmm promoter activity confirmed the relationship between bmm expression and obesity. Drosophila flies administered with high-glucose diets showed higher lipid contents, indicating the obesity phenotype, whereas weaker intensity of the GFP signal as well as reduced bmm mRNA expression. These results demonstrated this transgenic Drosophila model is obviously useful for screening anti-obesity agents. Lsd1’s function as a regulator of lipolysis in Drosophila has been demonstrated while its functions during development are still under investigation. In order to determine the function of Lsd1 during development, Lsd1 was knocked down in Drosophila using the GAL4-UAS system. Selective knockdown of Lsd1 in the dorsal wing disc caused an atrophied wing phenotype. The generation of reactive oxygen species in the wing pouch compartment of the Lsd1-knockdown flies was significantly higher than in the control. Immunostaining with caspase-3 antibody revealed a greater number of apoptotic cells in Lsd1-knockdown wing discs than in the control. Cell death by autophagy was induced in the knockdown flies. Moreover, cells deprived of Lsd1 showed mitochondrial expansion and decreased ATP levels. These results highlight the roles of Drosophila Lsd1 during wing development.

博士（学術）

京都工芸繊維大学

14303甲第809号

http://hdl.handle.net/10212/2345

eng

ETD

Thesis or Dissertation

Thesis