Inukai T
Graduate School of Agriculture, Hokkaido University, 060-8589 Sapporo, Japan.
Mol Genet Genomics. 2004 Mar;271(2):220-7. doi: 10.1007/s00438-003-0973-5. Epub 2004 Feb 4.
A survey of minisatellites (MSs) in 5.3 Mb of randomly selected rice DNA sequences from public databases was carried out to clarify the role of transposable elements (TEs) in the dispersal of MSs in the rice genome. The estimated frequency of MSs in this sample was one per 23.4 kb, and this frequency is approximately equivalent to that of Class I microsatellites in the rice genome. Of the MSs in the 5.3-Mb sequence sample, 82% were found to be present in multiple copies in the rice genome, and all of these were a part of TE sequences. In this study at least 61 TE groups were identified as MS carriers. It was also shown that the GC-rich MS pOs6.2H, which was previously reported to be one of the interspersed MSs in the rice genome, is a component of an En/Spm-like element. These results indicate that the majority of MSs in the rice genome are maintained in TEs, and amplified and dispersed as components of the TEs. The G+C content of the multi-locus MS sequences reflected that of the TE sequences containing those MSs, but no obvious bias towards the high G+C content of DNA was observed. Single locus MSs also did not show any obvious bias towards the high G+C content of DNA in the rice genome. In this respect, the MSs in the rice genome are quite different from those in the human genome: in the latter, the majority of MSs show an obvious bias towards the high G+C content of DNA.
为了阐明转座元件（TEs）在水稻基因组中小卫星（MSs）扩散中的作用，我们对来自公共数据库的5.3 Mb随机选择的水稻DNA序列中的小卫星进行了调查。该样本中小卫星的估计频率为每23.4 kb一个，这个频率与水稻基因组中I类微卫星的频率大致相当。在5.3 Mb序列样本中的小卫星中，82%在水稻基因组中以多拷贝形式存在，并且所有这些都是TE序列的一部分。在这项研究中，至少61个TE组被鉴定为MS载体。研究还表明，富含GC的MS pOs6.2H，先前报道它是水稻基因组中散布的MSs之一，是一个En/Spm样元件的组成部分。这些结果表明，水稻基因组中的大多数MSs存在于TEs中，并作为TEs的组成部分进行扩增和扩散。多位点MS序列的G+C含量反映了包含这些MSs的TE序列的G+C含量，但未观察到对DNA高G+C含量的明显偏向。单一位点的MSs在水稻基因组中也未显示出对DNA高G+C含量的任何明显偏向。在这方面，水稻基因组中的MSs与人类基因组中的MSs有很大不同：在人类基因组中，大多数MSs对DNA的高G+C含量表现出明显的偏向。
