Gotea Valer, Makałowski Wojciech
Institute of Molecular Evolutionary Genetics and Department of Biology, Center for Comparative Genomics and Bioinformatics, The Pennsylvania State University, University Park, PA 16802, USA.
Trends Genet. 2006 May;22(5):260-7. doi: 10.1016/j.tig.2006.03.006. Epub 2006 Mar 29.
Recent studies indicate that the initial classification of transposable elements (TEs) as 'useless', 'selfish' or 'junk' pieces of DNA is not an accurate one. TEs seem to have complex regulatory functions and contribute to the coding regions of many genes. Because this contribution had been documented only at transcript level, we searched for evidence that would also support the translation of TE cassettes. Our findings suggest that the proportion of proteins with TE-encoded fragments (approximately 0.1%), although probably underestimated, is much less than what the data at transcript level suggest (approximately 4%). In all cases, the TE cassettes are derived from old TEs, consistent with the idea that incorporation (exaptation) of TE fragments into functional proteins requires long evolutionary periods. We therefore argue that functional proteins are unlikely to contain TE cassettes derived from young TEs, the role of which is probably limited to regulatory functions.
最近的研究表明，将转座元件（TEs）最初归类为DNA的“无用”“自私”或“垃圾”片段并不准确。TEs似乎具有复杂的调控功能，并对许多基因的编码区域有贡献。由于这种贡献仅在转录水平得到记录，我们寻找了也能支持TE盒翻译的证据。我们的研究结果表明，含有TE编码片段的蛋白质比例（约0.1%），尽管可能被低估，但远低于转录水平数据所显示的比例（约4%）。在所有情况下，TE盒都源自古老的TEs，这与TE片段整合（适应性借用）到功能蛋白中需要漫长进化时期的观点一致。因此，我们认为功能蛋白不太可能含有源自年轻TEs的TE盒，年轻TEs的作用可能仅限于调控功能。
