The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, LinAn, China.
J Plant Res. 2011 Sep;124(5):607-17. doi: 10.1007/s10265-010-0396-4. Epub 2010 Dec 17.
Mariner-like elements (MLEs) are the most diverse and widespread transposable elements, with members of the MLE superfamily found in fungi, plants, ciliates and animals. In a previous study, we characterized 82 MLE transposase gene fragments (average length 383 bp) in 44 bamboo species, indicating that MLEs are widespread, abundant and diverse in the Bambusoideae subfamily. In this study, we isolated 79 full-length MLE transposase genes from 63 bamboo species representing 38 genera in six subtribes mainly found in China. The transposases were highly conserved, mostly uniform in length and contained intact DNA-binding motifs and DD39D catalytic domains with few notable frameshift, indel and nonsense mutations. This suggested the MLEs are probably still mobile, not yet affected by vertical inactivation. A phylogenetic tree of the Bambusoideae subfamily established using ribosomal DNA internal transcribed spacer sequences was incongruent with a second tree based on the MLE transposase genes. This evidence, together with the presence of near-identical MLEs in distantly related species and diverse MLEs in closely related species, indicates that MLEs have evolved in a distinct manner, probably independently of speciation events in the subfamily. The evolution and diversity of MLE transposase genes in the Bambusoideae subfamily is discussed.
内共生转座子（MLEs）是最具多样性和广泛分布的转座元件，在真菌、植物、纤毛虫和动物中都发现了 MLE 超家族的成员。在之前的研究中，我们在 44 种竹类植物中鉴定了 82 个 MLE 转座酶基因片段（平均长度 383bp），表明 MLE 在 Bambusoideae 亚科中广泛存在、丰富且多样。在本研究中，我们从 63 种主要分布在中国的 38 个属的竹类植物中分离出 79 个全长 MLE 转座酶基因。转座酶高度保守，长度基本一致，包含完整的 DNA 结合基序和 DD39D 催化结构域，仅有少数明显的移码、缺失和无义突变。这表明 MLE 可能仍然是活跃的，尚未受到垂直失活的影响。使用核糖体 DNA 内转录间隔区序列建立的 Bambusoideae 亚科系统发育树与基于 MLE 转座酶基因的第二个树不一致。这一证据，加上在远缘物种中存在几乎相同的 MLE 和在近缘物种中存在多样化的 MLE，表明 MLE 以独特的方式进化，可能独立于亚科的物种形成事件。本文讨论了 Bambusoideae 亚科 MLE 转座酶基因的进化和多样性。
