Kelly F D, Levin H L
Laboratory of Gene Regulation and Development, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
Cytogenet Genome Res. 2005;110(1-4):566-74. doi: 10.1159/000084990.
Recent studies of the LTR-retrotransposons of Schizosaccharomyces pombe have shed considerable light on their evolution and function. The sequencing of the S. pombe genome allowed analysis of its transposon content. This analysis provides information about the maintenance and loss of transposons in the genome. The results of transposition assays and biochemical analyses demonstrate that the N-terminal protein of Tf1 is functionally equivalent to the Gag proteins of retroviruses and retrotransposons. Despite this conservation of function, the N-terminal protein of Tf1 lacks any sequence similarity to other known Gag proteins. Sequence analysis and experimental data also indicate that the Tf1 transposons of S. pombe target their integration into specific sites in the host genome. Transposition events resulting from the expression of Tf1 reveal a strong preference for intergenic regions, specifically at pol II promoters in a window 100-400 bp upstream of open reading frames. The complete and partial copies of Tf transposons in the sequenced genome of S. pombe show the same association of integration with promoter regions. This body of work explores how the transposon interacts with the host, the balance between the transposons propagation and loss, and how different families of transposons evolve.
近期对粟酒裂殖酵母的LTR反转录转座子的研究,为其进化和功能提供了相当多的见解。粟酒裂殖酵母基因组的测序使得对其转座子含量进行分析成为可能。该分析提供了有关基因组中转座子的维持和丢失的信息。转座试验和生化分析的结果表明,Tf1的N端蛋白在功能上等同于逆转录病毒和反转录转座子的Gag蛋白。尽管功能上存在这种保守性,但Tf1的N端蛋白与其他已知Gag蛋白没有任何序列相似性。序列分析和实验数据还表明,粟酒裂殖酵母的Tf1转座子将其整合靶向宿主基因组中的特定位点。由Tf1表达导致的转座事件显示出对基因间区域有强烈偏好,特别是在开放阅读框上游100 - 400 bp窗口内的聚合酶II启动子处。粟酒裂殖酵母测序基因组中Tf转座子的完整和部分拷贝显示出整合与启动子区域的相同关联。这项工作探讨了转座子如何与宿主相互作用、转座子增殖与丢失之间的平衡,以及不同转座子家族如何进化。