Kim A, Terzian C, Santamaria P, Pélisson A, Purd'homme N, Bucheton A
Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France.
Proc Natl Acad Sci U S A. 1994 Feb 15;91(4):1285-9. doi: 10.1073/pnas.91.4.1285.
Retroviruses are commonly considered to be restricted to vertebrates. However, the genome of many eukaryotes contains mobile sequences known as retrotransposons with long terminal repeats (LTR retrotransposons) or viral retrotransposons, showing similarities with integrated proviruses of retroviruses, such as Ty elements in Saccharomyces cerevisiae, copia-like elements in Drosophila, and endogenous proviruses in vertebrates. The gypsy element of Drosophila melanogaster has LTRs and contains three open reading frames, one of which encodes potential products similar to gag-specific protease, reverse transcriptase, and endonuclease. It is more similar to typical retroviruses than to LTR retrotransposons. We report here experiments showing that gypsy can be transmitted by microinjecting egg plasma from embryos of a strain containing actively transposing gypsy elements into embryos of a strain originally devoid of transposing elements. Horizontal transfer is also observed when individuals of the "empty" stock are raised on medium containing ground pupae of the stock possessing transposing elements. These results suggest that gypsy is an infectious retrovirus and provide evidence that retroviruses also occur in invertebrates.
逆转录病毒通常被认为只存在于脊椎动物中。然而，许多真核生物的基因组中含有被称为逆转座子的可移动序列，这些序列具有长末端重复序列（LTR逆转座子）或病毒逆转座子，与逆转录病毒的整合前病毒有相似之处，比如酿酒酵母中的Ty元件、果蝇中的类copia元件以及脊椎动物中的内源性前病毒。黑腹果蝇的gypsy元件具有长末端重复序列，包含三个开放阅读框，其中一个编码的潜在产物类似于gag特异性蛋白酶、逆转录酶和核酸内切酶。它与典型的逆转录病毒比与LTR逆转座子更为相似。我们在此报告的实验表明，通过将含有活跃转座的gypsy元件的品系胚胎的卵细胞质显微注射到原本没有转座元件的品系胚胎中，gypsy可以实现传播。当“无元件”品系的个体在含有具有转座元件品系的研磨蛹的培养基上饲养时，也能观察到水平转移。这些结果表明gypsy是一种传染性逆转录病毒，并为逆转录病毒也存在于无脊椎动物中提供了证据。
