DeMarco Ricardo, Machado Abimael A, Bisson-Filho Alexandre W, Verjovski-Almeida Sergio
Departamento de Bioquimica, Instituto de Quimica, Universidade de São Paulo, Brazil.
Biochem Biophys Res Commun. 2005 Jul 22;333(1):230-40. doi: 10.1016/j.bbrc.2005.05.080.
This work describes 18 new transcribed retrotransposons of the blood fluke Schistosoma mansoni. Among them, 9 were LTR, 8 non-LTR, and 1 Penelope-like element (PLE) retrotransposon. Sequences were generated by in silico reconstruction using S. mansoni ESTs and transcripts obtained by rapid amplification of cDNA ends, complemented in some cases by sequencing of genomic clones amplified by PCR. A novel element from the ancient R2/R4/CRE transposon group is described for the first time in S. mansoni. In addition, one non-LTR retrotransposon family displays long (40-450 bp) 3'-UTR with at least six different transcribed sequences among the copies, five LTR retrotransposons have abundantly transcribed incomplete copies lacking the sequence segment coding for the reverse transcriptase domain, and four non-LTR retrotransposons code for DNA-binding PHD domains that may give them a differential targeting. These results allow for a comprehensive description of the transcribed retrotransposon diversity of this complex human parasite.
这项研究描述了曼氏血吸虫18个新的转录反转录转座子。其中，9个是长末端重复序列（LTR）反转录转座子，8个是非LTR反转录转座子，1个是类佩内洛普元件（PLE）反转录转座子。序列通过利用曼氏血吸虫的表达序列标签（EST）进行电子重建以及通过cDNA末端快速扩增获得的转录本生成，某些情况下还通过对PCR扩增的基因组克隆进行测序来补充。首次在曼氏血吸虫中描述了一个来自古老的R2/R4/CRE转座子家族的新元件。此外，一个非LTR反转录转座子家族具有长（40 - 450 bp）的3'非翻译区（UTR），其拷贝中有至少六种不同的转录序列，五个LTR反转录转座子有大量转录的不完整拷贝，缺少编码逆转录酶结构域的序列片段，四个非LTR反转录转座子编码可能赋予它们不同靶向性的DNA结合植物同源结构域（PHD）。这些结果使得对这种复杂人体寄生虫转录反转录转座子多样性有了全面的描述。
