栽培大豆端粒相关序列的克隆及定位

Cloning and Mapping of Telomere Associated Sequence in Soybean

以拟南芥的端粒重复序列(TR)为引物(TTTAGGG)3,在栽培大豆中扩增并克隆了1个574bp的DNA片段。序列分析表明:该片段与大豆端粒相关序列的相似度高达92%～99%,与白玉草TR-TAS的间隔区的相似度为79%,与大麦和玉米等其它植物的TAS的相似度在16%～35%之间;这一片段含有14个拷贝的拟南芥类型端粒重复单元,并且还有30个重复单元发生了碱基突变(缺失、替换与插入)。该端粒相关序列具有1个25bp的保守重复单元,串联重复13个拷贝,且该序列的A+T含量高于60%,体现了卫星DNA的特征。该序列被定位在大豆3号染色体的近末端。

Using the Arabidopsis-type telomeric repeat（TTTAGGG） 3 as a primer,a 574 bp TAS was amplified and cloned from three soybean（Glycine max） cultivars.Sequence analysis indicated that the similarities of the TASs from different cultivars in this study and other TASs from GenBank ranged from 92% to 99%.A similarity of 79% was detected between the TAS obtained and the interval sequence of TR-TAS from Silene latifolia.Low similarities ranging from 16% to 35% were observed between the soybean TAS and other plants such as barley（Hordeum vulgare） and corn（Zea mays）.In this TAS fragment,there were 14 copies of Arabidopsis-type telomeric repeat（TTTAGGG/CCCTAAA） and 30 copies of mutation motifs with deletion,substitution and inversion.The 25 bp conserved tandem repeat in this TAS fragment occurred in 13 copies and the content of adenine and thymine（A ＋ T） was greater than 60%,showing the characterization of satellite DNA.This TAS fragment was mapped to the proximal end of soybean chromosome 3.