Koyama H, Takita E, Kawamura A, Hara T, Shibata D
Laboratory of Plant Cell Technology, Faculty of Agriculture, Gifu University, Japan.
Plant Cell Physiol. 1999 May;40(5):482-8. doi: 10.1093/oxfordjournals.pcp.a029568.
A mitochondrial citrate synthase (CS) of Arabidopsis thaliana was introduced into carrot (Daucus carota L. cv. MS Yonsun) cells by Agrobacterium tumefaciens-mediated transformation. Transgenic cell lines had high CS activity, the highest value observed was 0.24 mumol (mg protein)-1 min-1 which was 1.9-fold of that in wild-type cells. Transcript levels of DcCS were similar between transgenic lines, but those of AtCS were increased as the CS activity of cells was increased. Isoelectric focussing revealed that the CS polypeptide of the transgenic lines had a pI value different from that of the wild-type cells, although the molecular mass was the same. These results indicate that the CS polypeptides of A. thaliana were expressed and processed to the mature form in carrot cells. The growth rate and excretion was 2.2-2.8 and 2.8-4.0 fold greater in the transgenic cells than in the wild type cells, respectively. Phosphate uptake from Al-phosphate also increased in transgenic cells. It appears, the overexpression of mitochondrial citrate synthase in carrot cells improves the growth rate in Al-phosphate medium possibly as a result of increased citrate excretion.
通过根癌农杆菌介导的转化，将拟南芥的线粒体柠檬酸合酶（CS）导入胡萝卜（Daucus carota L. cv. MS Yonsun）细胞。转基因细胞系具有较高的CS活性，观察到的最高值为0.24 μmol（mg蛋白）-1 min-1，是野生型细胞的1.9倍。转基因系之间DcCS的转录水平相似，但AtCS的转录水平随着细胞CS活性的增加而升高。等电聚焦显示，尽管分子量相同，但转基因系的CS多肽的pI值与野生型细胞不同。这些结果表明，拟南芥的CS多肽在胡萝卜细胞中表达并加工成成熟形式。转基因细胞的生长速率和排泄量分别比野生型细胞高2.2 - 2.8倍和2.8 - 4.0倍。转基因细胞从磷酸铝中吸收磷酸盐也有所增加。看来，胡萝卜细胞中线粒体柠檬酸合酶的过表达可能由于柠檬酸排泄增加而提高了在磷酸铝培养基中的生长速率。
