Palauqui J C, Elmayan T, Pollien J M, Vaucheret H
Laboratoire de Biologie Cellulaire, INRA, Versailles, France.
EMBO J. 1997 Aug 1;16(15):4738-45. doi: 10.1093/emboj/16.15.4738.
Using grafting procedures, we investigated the transmission of co-suppression of nitrate reductase and nitrite reductase host genes and transgenes and of post-transcriptional silencing of a uidA transgene encoding glucuronidase in tobacco. We demonstrate that silencing is transmitted with 100% efficiency from silenced stocks to non-silenced scions expressing the corresponding transgene. Transmission is unidirectional from stock to scion, transgene specific, locus independent and requires the presence of a transcriptionally active transgene in the target scion. The transmission of co-suppression occurs when silenced stocks and non-silenced target scions are physically separated by up to 30 cm of stem of a non-target wild-type plant. Taken together, these results suggest that a non-metabolic, transgene-specific, diffusable messenger mediates the propagation of de novo post-transcriptional silencing through the plant.
利用嫁接方法,我们研究了烟草中硝酸还原酶和亚硝酸还原酶宿主基因与转基因的共抑制以及编码葡糖醛酸酶的uidA转基因的转录后沉默的传递情况。我们证明,沉默以100%的效率从沉默的砧木传递到表达相应转基因的未沉默接穗。传递是从砧木到接穗单向的、转基因特异性的、位点独立的,并且需要目标接穗中存在转录活性的转基因。当沉默的砧木和未沉默的目标接穗被非目标野生型植物长达30厘米的茎物理隔开时,共抑制仍会发生。综上所述,这些结果表明,一种非代谢性的、转基因特异性的、可扩散的信使介导了从头转录后沉默在植物中的传播。