甘蓝型油菜及近缘种中异质型ACCase亚基accd编码基因的克隆及序列分析

采用RT-PCR方法，以甘蓝型油菜、甘蓝、芥菜型油菜和白菜型油菜的幼嫩叶片cDNA为模板对异质型乙酰辅酶A羧化酶（ACCase）的β-CT亚基（羧基转移酶）的accd编码基因进行扩增，得到长度分别为1470bp、1470bp、1464bp和1464bp的编码序列，分别可编码490、490、488和488个氨基酸的蛋白质。序列分析表明，来自4个油菜近缘种的accd基因高度同源，编码的蛋白质都具有相似的锌指结构和C-末端5个相同的基元，其中基元I（GSMGSVVG）和基元II（PLIIVCASGGARMQE）在所有植物及大肠杆菌的β-CT亚基中普遍存在。Southern杂交显示该基因在甘蓝型油菜及其近缘种的基因组中呈单拷贝。

Cloning and Sequence Analysis of Heteromeric ACCase Subunit Encoding Gene accD from Four Close-related Species of Brassica

The cDNA fragments of accd gene encoding for subunit β-carboxyltransferase of heteromeric Acetyl-CoA carboxylase (ACCase) were amplified from young leaves cDNA of Brassica napus, Brassica oleracea, Brassica juncea and Brassica rapa by means of RT-PCR. The lengths of the amplified accd genes were 1470bp, 1470bp, 1464bp and 1464bp respectively. Sequence analysis showed that the cDNA sequences of the four accd genes shared high homology. The amino acid sequences deduced from the four accd genes contained the similar zinc finger structure and five same motifs on C-terminal regions, among which motif I (GSMGSVVG) and motif II (PLIIVCASGGARMQE) were present in β-carboxyltransferases of all plant species and E.coli. Southern blotting demonstrated that there was only a single copy of accd gene in genomes of the four close-related species of Brassica.