Ferbeyre G, Smith J M, Cedergren R
Département de Biochimie, Université de Montréal, Montréal, Québec, Canada H3C 3J7.
Mol Cell Biol. 1998 Jul;18(7):3880-8. doi: 10.1128/MCB.18.7.3880.
Using a computer program designed to search for RNA structural motifs in sequence databases, we have found a hammerhead ribozyme domain encoded in the Smalpha repetitive DNA of Schistosoma mansoni. Transcripts of these repeats are expressed as long multimeric precursor RNAs that cleave in vitro and in vivo into unit-length fragments. This RNA domain is able to engage in both cis and trans cleavage typical of the hammerhead ribozyme. Further computer analysis of S. mansoni DNA identified a potential trans cleavage site in the gene coding for a synaptobrevin-like protein, and RNA transcribed from this gene was efficiently cleaved by the Smalpha ribozyme in vitro. Similar families of repeats containing the hammerhead domain were found in the closely related Schistosoma haematobium and Schistosomatium douthitti species but were not present in Schistosoma japonicum or Heterobilharzia americana, suggesting that the hammerhead domain was not acquired from a common schistosome ancestor.
通过使用一个旨在在序列数据库中搜索RNA结构基序的计算机程序，我们在曼氏血吸虫的Smalpha重复DNA中发现了一个锤头状核酶结构域。这些重复序列的转录本以长的多聚体前体RNA形式表达，它们在体外和体内都能切割成单位长度的片段。这个RNA结构域能够进行锤头状核酶典型的顺式和反式切割。对曼氏血吸虫DNA的进一步计算机分析在编码突触小泡蛋白样蛋白的基因中确定了一个潜在的反式切割位点，并且从该基因转录的RNA在体外被Smalpha核酶有效切割。在密切相关的埃及血吸虫和杜氏血吸虫物种中发现了类似的包含锤头状结构域的重复序列家族，但日本血吸虫或美洲异毕吸虫中不存在，这表明锤头状结构域并非从共同的血吸虫祖先那里获得。
