毛竹Stowaway-like MITEs转座子的分离与分析

Isolation and Analysis of Stowaway-like MITEs from DNA Libraries Enriched in Phyllostachys edulis

微型颠倒重复序列(miniature inverted repeat transposable elements,MITEs)是一类对基因组进化和基因表达有重要调节作用的转座子。为分析MITEs在毛竹基因组中的分布特性,借鉴Fast Isolation by AFLP of Sequences Containing repeats(FIASCO)方法,首次构建Stowaway-like MITEs富集文库。随机挑取21个克隆,测序发现2个含有Stowaway-like MITEs序列(Stow-Ph1和Stow-Ph2),阳性率为9.52%。Stow-Ph1和Stow-Ph2的长度分别为260和258bp,具有Stowaway-like MITEs典型的末端颠倒重复序列(terminal inverted repeats,TIRs)和靶位点重复序列(target site duplication,TSD)。Stow-Ph1和Stow-Ph2与水稻的Stow-Os8(FJ266024)的同源性分别为46.4%和52.6%。Stow-Ph1和Stow-Ph2与水稻16类Stowaway-like MITEs的TIRs前20bp的相似性均高于50%,表明毛竹的Stowaway-like MITEs在TIRs上是高度保守的。

Transposable elements were a kind of DNA fragments movable in genomes. Miniature inverted repeat transposable elements （ MITEs） were a class of short,widespread transposable elements with high copy number which played an important role in evolution of genome and regulation of gene expression. In order to analyze the distribution and characteristics of MITEs in Phyllostachys edulis genome,DNA library enriched for Stowaway-like MITEs was firstly constructed by the method of FIASCO （Fast Isolation by AFLP of Sequences Containing repeats）. Totally 21 recombinant clones were randomly isolated with PCR method and then sequenced. Two clones （ Stow-Ph1 and Stow-Ph2 ） were identified as Stowaway-like MITEs. The rate of positive clones was 9. 52%. The fragment lengths of Stow-Ph1 and Stow-Ph2 were 260 bp and 258 bp,respectively. They had typical TIRs （ terminal inverted repeats） and TSD （ target site duplication） of Stowaway-like MITEs. The identity was 46. 4% between Stow-Ph1 and Stow-Os8 （ FJ266024 ）,and 52. 6% between Stow-Ph2 and Stow-Os8. The identities among Stow-Ph1,Stow-Ph2 and 16 rice Stowaway-like MITEs were above 50% based on the first 20 bp of their TIRs,which reflected that the TIRs of Stow-Ph1 and Stow-Ph2 were highly conserved.