Wilanowski T M, Gibson J B, Symonds J E
Molecular and Population Genetics Group, Research School of Biological Sciences, Australian National University, Canberra, Australia.
Proc Natl Acad Sci U S A. 1995 Dec 19;92(26):12065-9. doi: 10.1073/pnas.92.26.12065.
The insertion of the blood retrotransposon into the untranslated region of exon 7 of the sn-glycerol-3-phosphate dehydrogenase-encoding gene (Gpdh) in Drosophila melanogaster induces a GPDH isozyme-GPDH-4-and alters the pattern of expression of the three normal isozymes-GPDH-1 to GPDH-3. The process of transcript terminus formation inside the retrotransposon insertion reduces the level of the Gpdh transcript that contains exon 8 and increases the level of the transcript that contains exons 1-7. The induced GPDH-4 isozyme is a translation product of the three transcripts that contain fragments of the blood retrotransposon. The mechanism of mutagenesis by the blood insertion is postulated to involve the pause or termination of transcription within the blood sequence, which in turn is caused by the interference of a DNA-binding protein with the RNA polymerase. Thus, we show the formation of a new functional GPDH protein by the insertion of a transposable element and discuss the evolutionary significance of this phenomenon.
血液逆转座子插入黑腹果蝇中编码甘油 - 3 - 磷酸脱氢酶基因（Gpdh）外显子7的非翻译区，会诱导产生一种GPDH同工酶——GPDH - 4，并改变三种正常同工酶——GPDH - 1至GPDH - 3的表达模式。逆转座子插入位点内部转录本末端形成的过程会降低包含外显子8的Gpdh转录本水平，并增加包含外显子1 - 7的转录本水平。诱导产生的GPDH - 4同工酶是三种包含血液逆转座子片段的转录本的翻译产物。血液插入诱变的机制据推测涉及血液序列内转录的暂停或终止，而这又是由一种DNA结合蛋白对RNA聚合酶的干扰所导致的。因此，我们展示了通过转座元件插入形成一种新的功能性GPDH蛋白，并讨论了这一现象的进化意义。
