1. DRD1-Pol V-dependent self-silencing of an exogenous silencer restricts the non-cell autonomous silencing of an endogenous target gene.
- Author
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Dong, Li, Liu, Meng, Fang, Yuan-Yuan, Zhao, Jian-Hua, He, Xiang-Feng, Ying, Xiao-Bao, Zhang, Yi-Yue, Xie, Qi, Chua, Nam-Hai, and Guo, Hui-Shan
- Subjects
PLANT gene silencing ,GENETIC transcription ,GENE targeting ,TRANSGENES ,GENETIC code ,NUCLEOTIDE sequence ,PLANT genetics ,METHYLATION - Abstract
Summary In plants, the exogenous transgene transcribing inverted-repeat (exo- IR) sequences produces double-stranded RNAs that are processed by DCL4. The 21-nt small interfering RNAs generated function as mobile signals to trigger non-cell autonomous silencing of target endogenes in the neighboring 10-15 cells. The potential involvement of nuclear silencing pathway components in signal spreading or sensing in target cells is not clear. Here, we demonstrate that the exo- IR silencer (exo- Pdsi) is negatively autoregulated through methylation spreading, which acts in cis to reinforce the self-silencing of the silencer. Mutations affecting nuclear proteins DRD1 and Pol V (NRPE1 or NRPD2) relieved exo- Pdsi self-silencing, resulting in higher levels of Pdsi transcripts, which increased the non-cell autonomous silencing of endo- PDS. Our results suggest that in an experimental silencing pathway, methylation spreading on a silencer transgene may not have a direct endogenous plant counterpart when the protein-encoding gene is the target. DRD1-Pol V-dependent de novo methylation, by acting in cis to reinforce self-silencing of exo- IR, may play a role in restraining the inappropriate silencing of active protein-coding genes in plants. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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