Cabanos Cerrone, Kato Naoki, Amari Yoshiki, Fujiwara Keigo, Ohno Tomoki, Shimizu Kousuke, Goto Tsuyoshi, Shimada Masaya, Kuroda Masaharu, Masuda Taro, Takaiwa Fumio, Utsumi Shigeru, Nagaoka Satoshi, Maruyama Nobuyuki
Laboratory of Food Quality Design and Development, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan.
Transgenic Res. 2014 Aug;23(4):609-20. doi: 10.1007/s11248-014-9793-0. Epub 2014 Mar 28.
Soybean 7S globulin, known as β-conglycinin, has been shown to regulate human plasma cholesterol and triglyceride levels. Furthermore, the α' subunit of β-conglycinin has specifically been shown to possess low-density lipoprotein (LDL)-cholesterol-lowering activity. Therefore, accumulation of the α' subunit of β-conglycinin in rice seeds could lead to the production of new functional rice that could promote human health. Herein, we used the low-glutelin rice mutant 'Koshihikari' (var. a123) and suppressed its glutelins and prolamins, the major seed storage proteins of rice, by RNA interference. The accumulation levels of the α' subunit in the lines with suppressed glutelin and prolamin levels were >20 mg in 1 g of rice seeds, which is considerably higher than those in previous studies. Oral administration of the transgenic rice containing the α' subunit exhibited a hypocholesterolemic activity in rats; the serum total cholesterol and LDL cholesterol levels were significantly reduced when compared to those of the control rice (var. a123). The cholesterol-lowering action by transgenic rice accumulating the α' subunit induces a significant increase in fecal bile acid excretion and a tendency to increase in fecal cholesterol excretion. This is the first report that transgenic rice exhibits a hypocholesterolemic activity in rats in vivo by using the β-conglycinin α' subunit.
大豆7S球蛋白，即β-伴大豆球蛋白，已被证明可调节人体血浆胆固醇和甘油三酯水平。此外，β-伴大豆球蛋白的α'亚基已被明确证明具有降低低密度脂蛋白（LDL）胆固醇的活性。因此，β-伴大豆球蛋白α'亚基在水稻种子中的积累可能会培育出促进人类健康的新型功能性水稻。在此，我们使用了低谷蛋白水稻突变体“越光”（变种a123），并通过RNA干扰抑制其谷蛋白和醇溶蛋白，这两种是水稻主要的种子贮藏蛋白。谷蛋白和醇溶蛋白水平受到抑制的株系中，α'亚基在1克水稻种子中的积累量>20毫克，这比之前的研究结果要高得多。口服含有α'亚基的转基因水稻对大鼠具有降胆固醇活性；与对照水稻（变种a123）相比，血清总胆固醇和LDL胆固醇水平显著降低。积累α'亚基的转基因水稻的降胆固醇作用导致粪便胆汁酸排泄显著增加，粪便胆固醇排泄有增加趋势。这是首篇关于利用β-伴大豆球蛋白α'亚基在大鼠体内证明转基因水稻具有降胆固醇活性的报道。
