Cloning and characterization of MID1 interacting protein 1 (mid1ip1) from tiger puffer (Takifugu rubripes), and its gene expression in response to dietary bile acid and lipid levels

Abstract

Mid1ip1 plays important roles in lipogenesis and microtubule stabilization, but little relevant information has been reported in fish. In the present study, mid1ip1 cDNA of tiger puffer was cloned and characterized, and its expression in response to dietary bile acid and lipid levels was investigated following a feeding trial. Experimental diets with suitable (8.5 %) or high lipid level (12.5 %), with or without bile acid supplementation (0.02 % and 0.10 % in the suitable-lipid diet; 0.02 % in the high-lipid diet) were used in the feeding trial. The tiger puffer Mid1ip1, which is putative Mid1ip1 subtype B, shared moderate identity to its known orthologs of other teleost and much lower identity to human Mid1ip1. Mid1ip1 had high transcription in the muscle, skin, eye, and brain, but low expression levels in the liver, intestine, and spleen. The high dietary bile acid level (0.1 %) significantly (P < 0.05) reduced the hepatic mRNA expression of mid1ip1, but unexpectedly the dietary lipid level did not significantly (P > 0.05) affect the gene expression. Significantly positive correlation (R2 = 0.812, P = 0.000) was observed between hepatic mRNA expression of mid1ip1 and tubulin-α, but not between the gene expression of mid1ip1 and acetyl-CoA carboxylase β (R2 = -0.434, P = 0.106), in response to dietary treatments, indicating the potential roles of this Mid1ip1 subtype in microtubule stabilization rather than in lipogenesis. To our knowledge, this is the first study investigating the regulation of fish mid1ip1 expression by dietary nutrients.