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Summary Like metazoans, plants use small regulatoryRNAs (sRNAs) to direct gene expression. Several classes ofsRNAs, which are distinguished by their origin and biogenesis, exist in plants. Among them, microRNAs (miRNAs) andtrans‐acting small interferingRNAs (ta‐siRNAs) mainly inhibit gene expression at post‐transcriptional levels. In the past decades, plant miRNAs and ta‐siRNAs have been shown to be essential for numerous developmental processes, including growth and development of shoots, leaves, flowers, roots and seeds, among others. In addition, miRNAs and ta‐siRNAs are also involved in the plant responses to abiotic and biotic stresses, such as drought, temperature, salinity, nutrient deprivation, bacteria, virus and others. This review summarizes the roles of miRNAs and ta‐siRNAs in plant physiology and development.
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Functional dissection of the ARGONAUTE7 promoter
Abstract ARGONAUTES are the central effector proteins ofRNAsilencing which bind target transcripts in a smallRNA‐guided manner.Arabidopsis thalianahas 10ARGONAUTE(AGO) genes, with specialized roles inRNA‐directedDNAmethylation, post‐transcriptional gene silencing, and antiviral defense. To better understand specialization amongAGOgenes at the level of transcriptional regulation we tested a library of 1497 transcription factors for binding to the promoters ofAGO1,AGO10, andAGO7using yeast 1‐hybrid assays. A ranked list of candidateDNA‐bindingTFs revealed binding of theAGO7promoter by a number of proteins in two families: the miR156‐regulatedSPLfamily and the miR319‐regulatedTCPfamily, both of which have roles in developmental timing and leaf morphology. Possible functions forSPLandTCPbinding are unclear: we showed that these binding sites are not required for the polar expression pattern ofAGO7, nor for the function ofAGO7in leaf shape. NormalAGO7transcription levels and function appear to depend instead on an adjacent 124‐bp region. Progress in understanding the structure of this promoter may aid efforts to understand how the conservedAGO7‐triggeredTAS3pathway functions in timing and polarity.
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- Award ID(s):
- 9531011
- PAR ID:
- 10084625
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Plant Direct
- Volume:
- 3
- Issue:
- 1
- ISSN:
- 2475-4455
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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