The fly genome contains a single ortholog of the evolutionarily conserved transcription factor hepatocyte nuclear factor 4 (HNF4), a broadly and constitutively expressed member of the nuclear receptor superfamily. Like its mammalian orthologs, Drosophila HNF4 (dHNF4) acts as a critical regulator of fatty acid and glucose homeostasis. Because of its role in energy storage and catabolism, the insect fat body controls non-autonomous organs including the ovaries, where lipid metabolism is essential for oogenesis. The present paper used dHNF4 overexpression (OE) in the fat bodies and ovaries to investigate its potential roles in lipid homeostasis and oogenesis. When the developing fat body overexpressed dHNF4, animals exhibited reduced size and failed to pupariate, but no changes in body composition were observed. Conditional OE of dHNF4 in the adult fat body produced a reduction in triacylglycerol content and reduced oogenesis. Ovary-specific dHNF4 OE increased oogenesis and egg-laying, but reduced the number of adult offspring. The phenotypic effects on oogenesis that arise upon dHNF4 OE in the fat body or ovary may be due to its function in controlling lipid utilization.

苍蝇基因组包含进化上保守的转录因子肝细胞核因子 4 (HNF4) 的单个直系同源物，HNF4 是核受体超家族中广泛和组成性表达的成员。与其哺乳动物直向同源物一样，果蝇 HNF4 (dHNF4) 是脂肪酸和葡萄糖稳态的关键调节剂。由于其在能量储存和分解代谢中的作用，昆虫脂肪体控制包括卵巢在内的非自主器官，其中脂质代谢对于卵子发生至关重要。本论文使用脂肪体和卵巢中的 dHNF4 过表达 (OE) 来研究其在脂质稳态和卵子发生中的潜在作用。当发育中的脂肪体过度表达 dHNF4 时，动物的体型变小且无法化蛹，但未观察到身体成分的变化。成人脂肪体中 dHNF4 的条件性 OE 导致甘油三酯含量减少和卵子生成减少。卵巢特异性 dHNF4 OE 增加了卵子发生和产卵，但减少了成年后代的数量。脂肪体或卵巢中 dHNF4 OE 对卵子发生的表型影响可能是由于其在控制脂质利用方面的功能。