Kempken F, Kück U
Lehrstuhl für Allgemeine Botanik, Ruhr-Universität Bochum, Germany.
Bioessays. 1998 Aug;20(8):652-9. doi: 10.1002/(SICI)1521-1878(199808)20:8<652::AID-BIES8>3.0.CO;2-K.
Transposons are ubiquitous genetic elements discovered so far in all investigated prokaryotes and eukaryotes. In remarkable contrast to all other genes, transposable elements are able to move to new locations within their host genomes. Transposition of transposons into coding sequences and their initiation of chromosome rearrangements have tremendous impact on gene expression and genome evolution. While transposons have long been known in bacteria, plants, and animals, only in recent years has there been a significant increase in the number of transposable elements discovered in filamentous fungi. Like those of other eukaryotes, each fungal transposable element is either of class or of class II. While class I elements transpose by a RNA intermediate and employ reverse transcriptases, class II elements transpose directly at the DNA level. We present structural and functional features for such transposons that have been identified so far in filamentous fungi. Emphasis is given to specific advantages or unique features when fungal systems are used to study transposable elements, e.g., the evolutionary impact of transposons in coenocytic organisms and possible experimental approaches toward horizontal gene transfer. Finally, we focus on the potential of transposons for tagging and identifying fungal genes.
转座子是迄今在所有已研究的原核生物和真核生物中均被发现的普遍存在的遗传元件。与所有其他基因形成显著对比的是，转座元件能够移动至其宿主基因组内的新位置。转座子转座至编码序列以及引发染色体重排对基因表达和基因组进化具有巨大影响。虽然转座子在细菌、植物和动物中早已为人所知，但直到最近几年，丝状真菌中发现的转座元件数量才显著增加。与其他真核生物的转座子一样，每个真菌转座元件要么属于I类，要么属于II类。I类元件通过RNA中间体进行转座并利用逆转录酶，而II类元件则直接在DNA水平上进行转座。我们展示了迄今在丝状真菌中已鉴定出的此类转座子的结构和功能特征。重点阐述了利用真菌系统研究转座子时的特定优势或独特特征，例如转座子在多核生物中的进化影响以及水平基因转移的可能实验方法。最后，我们聚焦于转座子在标记和鉴定真菌基因方面的潜力。
