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Transcriptional and posttranscriptional gene silencing are mechanistically related 总被引:30,自引:0,他引:30
Sijen T Vijn I Rebocho A van Blokland R Roelofs D Mol JN Kooter JM 《Current biology : CB》2001,11(6):436-440
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Mallory AC Parks G Endres MW Baulcombe D Bowman LH Pruss GJ Vance VB 《Nature biotechnology》2002,20(6):622-625
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Ectopic DICER-LIKE1 expression in P1/HC-Pro Arabidopsis rescues phenotypic anomalies but not defects in microRNA and silencing pathways 总被引:1,自引:0,他引:1
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Mlotshwa S Schauer SE Smith TH Mallory AC Herr JM Roth B Merchant DS Ray A Bowman LH Vance VB 《The Plant cell》2005,17(11):2873-2885
Expression of the viral silencing suppressor P1/HC-Pro in plants causes severe developmental anomalies accompanied by defects in both short interfering RNA (siRNA) and microRNA (miRNA) pathways. P1/HC-Pro transgenic lines fail to accumulate the siRNAs that mediate RNA silencing and are impaired in both miRNA processing and function, accumulating abnormally high levels of miRNA/miRNA* processing intermediates as well as miRNA target messages. Both miRNA and RNA silencing pathways require participation of DICER-LIKE (DCL) ribonuclease III-like enzymes. Here, we investigate the effects of overexpressing DCL1, one of four Dicers in Arabidopsis thaliana, on P1/HC-Pro-induced defects in development and small RNA metabolism. Expression of a DCL1 cDNA transgene (35S:DCL1) produced a mild gain-of-function phenotype and largely rescued dcl1 mutant phenotypes. The 35S:DCL1 plants were competent for virus-induced RNA silencing but were impaired in transgene-induced RNA silencing and in the accumulation of some miRNAs. Ectopic DCL1 largely alleviated developmental anomalies in P1/HC-Pro plants but did not correct the P1/HC-Pro-associated defects in small RNA pathways. The ability of P1/HC-Pro plants to suppress RNA silencing and the levels of miRNAs, miRNA*s, and miRNA target messages in these plants were essentially unaffected by ectopic DCL1. These data suggest that P1/HC-Pro defects in development do not result from general impairments in small RNA pathways and raise the possibility that DCL1 participates in processes in addition to miRNA biogenesis. 相似文献
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A model for RNA-mediated gene silencing in higher plants 总被引:30,自引:0,他引:30
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Systemic silencing signal(s) 总被引:18,自引:0,他引:18
Grafting experiments have revealed that transgenic plants that undergo co-suppression of homologous transgenes and endogenous genes or PTGS of exogenous transgenes produce a sequence-specific systemic silencing signal that is able to propagate from cell to cell and at long distance. Similarly, infection of transgenic plants by viruses that carry (part of) a transgene sequence results in global silencing (VIGS) of the integrated transgenes although viral infection is localized. Systemic PTGS and VIGS strongly resemble recovery from virus infection in non-transgenic plants, leading to protection against secondary infection in newly emerging leaves and PTGS of transiently expressed homologous transgenes. The sequence-specific PTGS signal is probably a transgene product (for example, aberrant RNA) or a secondary product (for example, RNA molecules produced by an RNA-dependent RNA polymerase with transgene RNA as a matrix) that mimics the type of viral RNA that is targeted for degradation by cellular defence. Whether some particular cases of transgene TGS could also rely on the production of such a mobile molecule is discussed. 相似文献