Functional analysis of Foxo1 and PPRA. possibly involved in the species-specific lipid accumulation of fish

我们克隆了来自torafugu的Foxo 1的完整开放阅读框架。转录本广泛分布于各种组织中。与哺乳动物同源物一样，在体外，torafugu Foxo 1蛋白以胰岛素样生长因子I（IGF-I）依赖的方式从细胞核排出，并与过氧化物酶体增殖物激活受体γ（PPARγ）结合。另一方面，过氧化物酶体增殖物激活受体γ（PPARγ）及其靶蛋白脂酶（LPL）的mRNA表达水平与鱼体肝脏和肌肉的脂肪含量呈良好的相关性。这些结果表明，过氧化物酶体增殖物激活受体γ促进了鱼类的种属特异性脂质积累，而Foxo 1是一种IGF依赖的过氧化物酶体增殖物激活受体γ抑制剂。

We cloned the full open reading frame of Foxo1 from torafugu. The transcripts were widely distributed in various tissues. Like the mammalian orthologues, torafugu Foxo1 protein was excluded from nucleus in a insulin-like growth factor I(IGF-I)-dependent manner, and bound to peroxisome proliferator-activated receptorγ(PPARγ) in vitro. On the other hand, the mRNA levels of PPARγand its putative target, lipoprotein lipase(LPL), showed a good correlation with the lipid content of liver and muscle in torafugu and red seabream. These results suggest that PPARγpromotes the species-specific lipid accumulation in fish, and Foxo1 functions as an IGF-dependent inhibitor of PPARγ.