水葫芦胞质型谷氨酰胺合成酶EcGS1全长cDNA的克隆及序列分析

Cloning and Analysis of Cytosolic Glutamine Synthetase cDNA from Eichharnia crassipes

以水葫芦根部总RNA逆转录得到的cDNA为模板,参照其他植物的胞质型谷氨酰胺合成酶(GS1)氨基酸保守序列设计简并引物,进行PCR扩增,以得到的产物为基础,采用RACE技术获得水葫芦胞质型谷氨酰胺合成酶EcGS1全长cDNA。全长为1 434 bp,开放阅读框为1 071 bp,编码356个氨基酸,分子量为39.3 kD,等电点pI为5.52。序列相似性分析显示,该序列与其他植物的GS1氨基酸序列具有较高的相似性。通过亚细胞定位预测,确定EcGS1为胞质型谷氨酰胺合成酶。

In this study, the template cDNA which was reversely transcribed from the total RNA of Eichharnia crassipes, was subjected to polymerase chain reaction（PCR）with the degenerate primers which was designed according to sequences of the Cytosolic Glutamine Synthetase（GS1）from other plants. The full-length cDNA sequence was achieved with Rapid Amplification of cDNA End method（RACE） from the amplification product. It includes 1 434 bp with the open reading frame of 1 071 bp which encoded 356 coding amino acids with a predicted size of 39.3 kD and a calculated pI of 5.52. The result of sequence homology analysis showed that the deduced protein had relatively high amino acid identity with GS1s from other plants. The prediction of sub-cellular localization showed that EcGS1 is a cytosolic glutamine synthetase.