GaTE Lab, Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, 277, Sala 153, Butantã, 05508-090, São Paulo, SP, Brazil.
Mol Genet Genomics. 2012 Mar;287(3):205-19. doi: 10.1007/s00438-011-0670-8. Epub 2012 Jan 7.
Transposons are abundant components of eukaryotic genomes, and play important role in genome evolution. The knowledge about these elements should contribute to the understanding of their impact on the host genomes. The hAT transposon superfamily is one of the best characterized superfamilies in diverse organisms, nevertheless, a detailed study of these elements was never carried in sugarcane. To address this question we analyzed 32 cDNAs similar to that of hAT superfamily of transposons previously identified in the sugarcane transcriptome. Our results revealed that these hAT-like transposases cluster in one highly homogeneous and other more heterogeneous lineage. We present evidences that support the hypothesis that the highly homogeneous group is a domesticated transposase while the remainder of the lineages are composed of transposon units. The first is common to grasses, clusters significantly with domesticated transposases from Arabidopsis, rice and sorghum and is expressed in different tissues of two sugarcane cultivars analyzed. In contrast, the more heterogeneous group represents at least two transposon lineages. We recovered five genomic versions of one lineage, characterizing a novel transposon family with conserved DDE motif, named SChAT. These results indicate the presence of at least three distinct lineages of hAT-like transposase paralogues in sugarcane genome, including a novel transposon family described in Saccharum and a domesticated transposase. Taken together, these findings permit to follow the diversification of some hAT transposase paralogues in sugarcane, aggregating knowledge about the co-evolution of transposons and their host genomes.
转座子是真核生物基因组中的丰富成分，在基因组进化中发挥重要作用。对这些元件的了解应该有助于理解它们对宿主基因组的影响。hAT 转座子超家族是在各种生物体中被研究得最好的超家族之一，然而，这些元件的详细研究从未在甘蔗中进行过。为了解决这个问题，我们分析了 32 个与先前在甘蔗转录组中鉴定的 hAT 超家族转座子相似的 cDNA。我们的结果表明，这些 hAT 样转座酶聚集成一个高度同源的和另一个更异质的谱系。我们提出了支持以下假设的证据，即高度同源的组是一种驯化的转座酶，而其余的谱系由转座子单元组成。第一个是普遍存在于禾本科植物中的，与拟南芥、水稻和高粱中的驯化转座酶聚类显著，并在两种甘蔗品种的不同组织中表达。相比之下，更异质的组代表至少有两个转座子谱系。我们恢复了一个谱系的五个基因组版本，鉴定了一个具有保守 DDE 基序的新转座子家族，命名为 SChAT。这些结果表明，甘蔗基因组中至少存在三个不同的 hAT 样转座酶旁系同源物谱系，包括在甘蔗中描述的一个新的转座子家族和一个驯化的转座酶。总之，这些发现允许我们跟踪甘蔗中一些 hAT 转座酶旁系同源物的多样化，增加了关于转座子及其宿主基因组的共同进化的知识。
