油菜含MATH结构域基因BnaMT1的克隆及表达分析

利用已构建的甘蓝型油菜种子发育过程SSH文库,筛选得到1个含MATH结构域的EST序列,并以其为信息探针,经电子克隆获得了该基因的全长cDNA,命名为BnaMT-1。BnaMT-1的开放阅读框(ORF)全长1 209 bp,编码402个氨基酸,相对分子质量为46 130.7,预测的理论等电点为8.50,其结构包括信号肽、跨膜结构及2个连续的MATH结构域,为亲水性胞外分泌蛋白;进化树分析发现,该基因与拟南芥含MATH结构域基因亲缘关系较近;利用半定量RT-PCR技术对该基因在甘蓝型油菜湘油15号不同组织及种子不同发育时期的表达分析表明:BnaMT-1在叶、花和果荚中都有表达,在根和茎中没有表达;种子发育过程中,BnaMT-1均有表达,且表达量于花后30～35 d最高,之后表达量下降。推测该基因可能与种子发育及油脂合成代谢相关。

Cloning and expression analysis of a MATHdomaingene BnaMT1 in Brassica napus

An EST sequence containing MATH domain was selected from the SSH library constructed from the developing seeds. According to the sequence, a full cDNA was cloned using in silico cloning, named BnaMT1. BnaMT1 contained 1 209 bp and encoded a hydrophilic secretory protein of 402 amino acid residues containing a signal peptide, a transmembrane domain and two MATH domains. The estimated molecular weight and isoelectric point of the putative protein were 46 130.7 and 8.50, respectively. Phylogenetic analysis showed that BnaMT1 was closely related to Arabidopsis thaliana. The expression map was done in the whole plant and at different developmental stages of seeds by semiRTPCR. The results showed that BnaMT1 was expressed in leaf, flower and silique, but not in root and stem. BnaMT1 was expressed through the seed developmental stages with the expression first up-regulated, then kept at the highest level from 30 days to 35 days after flowering, and down-regulated afterwards. It was inferred that the function of BnaMT1 gene may be related to seed development.