He H, Rovira C, Recco-Pimentel S, Liao C, Edström J E
Department of Molecular Genetics, University of Lund, Sweden.
J Mol Biol. 1995 Jan 6;245(1):34-42. doi: 10.1006/jmbi.1994.0004.
A short interspersed repeat (SINE) in the two sibling species Chironomus pallidivittatus and Chironomus tentans is described. It is present at many sites in the genome and is surrounded by 10 to 14 bp target site duplications. It consists of two sequence modules in different numbers and variable order relative to each other and often has large inversions of different sizes at one end. One of the modules contains pol III promoter consensus sequences. This SINE, nevertheless, is likely to have been dependent on an outside promoter for its formation. It is therefore interesting that both modules start with a 22 bp region with striking similarity to the R2 insertion site in the preribosomal gene of insects. We suggest that this type of SINE, termed Cp1, was formed after a series of events among which the first step was the retroposition of a tRNA gene into the R2 site in the preribosomal gene by the R2 coded protein. The final step is likely to have been due to retroposition from this site.
描述了摇蚊（Chironomus pallidivittatus）和直突摇蚊（Chironomus tentans）这两个姊妹物种中的一种短散在重复序列（SINE）。它存在于基因组的许多位点，周围有10至14个碱基对的靶位点重复序列。它由两个序列模块组成，数量不同且彼此相对顺序可变，并且在一端常常有不同大小的大倒位。其中一个模块包含聚合酶III启动子共有序列。然而，这种SINE可能在其形成过程中依赖于外部启动子。因此有趣的是，两个模块都起始于一个22个碱基对的区域，该区域与昆虫前核糖体基因中的R2插入位点具有惊人的相似性。我们认为，这种类型的SINE，称为Cp1，是在一系列事件之后形成的，其中第一步是tRNA基因通过R2编码的蛋白质反转录到前核糖体基因的R2位点。最后一步可能是由于从该位点的反转录。
