Voytas D F, Ausubel F M
Department of Genetics, Harvard Medical School, Boston, Massachusetts.
Nature. 1988 Nov 17;336(6196):242-4. doi: 10.1038/336242a0.
The fast generation time, small genome size and extensive genetic map of the crucifer Arabidopsis thaliana have made it the subject of an increasing number of studies in plant molecular genetics. As transposable elements have greatly facilitated genetic analysis in a variety of species, we have attempted to identify an endogenous A. thaliana transposable element. We report here the discovery of a family of such elements, which we refer to as Ta1 elements. Sequence analysis of one such element shows that it is closely related to retrotransposons and integrated retroviral proviruses, being bound by a direct sequence repeat and having an open reading frame with clear sequence similarity to the polyprotein of the Drosophila melanogaster retrotransposon copia. The sequence of an empty target site of a Ta1 element shows that insertion is accompanied by a five-base-pair target-site duplication and that Ta1 has transposed in the period of time since divergence of two races of A. thaliana.
十字花科植物拟南芥繁殖周期短、基因组小且遗传图谱丰富,这使得它成为植物分子遗传学领域中越来越多研究的对象。由于转座元件极大地促进了多种物种的遗传分析,我们试图鉴定一种内源性拟南芥转座元件。我们在此报告发现了这样一类元件,我们将其称为Ta1元件。对其中一个元件的序列分析表明,它与逆转座子和整合的逆转录病毒前病毒密切相关,由一个直接序列重复序列界定,并有一个开放阅读框,其序列与果蝇逆转座子copia的多聚蛋白有明显的序列相似性。一个Ta1元件空靶位点的序列表明,插入伴随着一个五碱基对的靶位点重复,并且Ta1在两个拟南芥种族分化后的一段时间内发生了转座。