Second site mutagenesis of a hypomorphic ago1 allele identifies SKI3 as an endogenous suppressor of PTGS

Yu, A., Saudemont, B., Bouteiller, N., Elvira-Matelot, E., Lepere, G., Parent, J. S., Morel, J. B., Cao, J., Elmayan, T., Vaucheret, H. (2015) Second site mutagenesis of a hypomorphic ago1 allele identifies SKI3 as an endogenous suppressor of PTGS. Plant Physiol, 169 (2). pp. 1266-1274. ISSN 1532-2548 (Electronic)0032-0889 (Linking)

URL: http://www.ncbi.nlm.nih.gov/pubmed/26286717
DOI: 10.1104/pp.15.00585

Abstract

Second site mutagenesis was performed on the ago1-33 hypomorphic mutant, which exhibits reduced sense transgene post-transcriptional gene silencing (S-PTGS). Mutations in FRY1, a positive regulator of the cytoplasmic 5'-to-3' exoribonuclease XRN4, and in SKI3, a member of the SKI complex that threads RNAs directly to the 3'-to-5' exoribonuclease of the cytoplasmic exosome, compensated AGO1 partial deficiency and restored S-PTGS with 100% efficiency. Moreover, xrn4 and ski3 single mutations provoked the entry of non-silenced transgenes into S-PTGS and enhanced S-PTGS on partially silenced transgenes, indicating that cytoplasmic 5'-to-3' and 3'-to-5' RNA degradation generally counteract S-PTGS, likely by reducing the amount of transgene aberrant RNAs that are used by the S-PTGS pathway to build up siRNAs that guide transgene RNA cleavage by AGO1. Constructs generating improperly terminated transgene mRNAs were not more sensitive to ski3 or xrn4 than regular constructs, suggesting that improperly terminated transgene mRNAs not only are degraded from both the 3' end but also from the 5' end, likely after decapping. The fact that impairment of either 5'-to-3' or 3'-to-5' RNA degradation is sufficient to provoke the entry of transgene RNA into the S-PTGS pathway whereas simultaneously impairment of both pathways is necessary to provoke the entry of endogenous mRNA into the S-PTGS pathway suggest poor RNA quality upon transcription of transgenes integrated at random genomic locations.

Item Type: Paper
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > argonaute proteins
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > genes, structure and function > gene regulation
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > genes, structure and function > gene regulation

bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein expression > post transcriptional modification
CSHL Authors:
Communities: CSHL labs > Martienssen lab
Depositing User: Matt Covey
Date Deposited: 20 Oct 2015 19:42
Last Modified: 20 Oct 2015 19:42
Related URLs:
URI: http://repository.cshl.edu/id/eprint/31940

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