Ágnes Dalmadi, Fabio Miloro, Auwalu Abdu, András Kis, Zoltán Havelda
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引用次数: 0
Abstract
RNA interference mediated via the action of micro RNAs (miRNAs) plays a pivotal role in developmental and stress response pathways. In the nucleus, plant miRNAs are generated by subsequent enzymatic cuts of the MIRNA precursors, having specific hairpin-like secondary structures, to liberate the miRNA/miRNA* duplex. The mature miRNA strands are then loaded mostly into the ARGONAUTE 1-containing RNA induced silencing complex (RISC) with various efficiencies and trigger the down-regulation of the expression of the target mRNAs, while the miRNA* strands are eliminated. Here we revealed that MIRNA precursor structural elements, not overlapping with the miRNA/miRNA* duplex part, can have an influence on the AGO-loading efficiency of the produced miRNAs. Using transient and transgenic expression studies, we revealed that a chimeric MIR168 precursor hairpin structure containing the stem region of a hvu-MIR171 precursor can induce the enhancement of AGO-loading efficiency of the produced miR168, resulting in increased target down-regulation and in developmental defects of the transgenic plants. This effect was the most pronounced when the orientation of the wild-type miR168/miR168* duplex was inverted in the chimeric precursor, implying the cooperative action of the structural elements. In transient studies, we also showed that precursor elements of MIR168a can reduce AGO-loading efficiency of miR171. The discovery of signals on remote structures of the miRNA precursor suggests that miRNA biogenesis and AGO-loading can be spatially more connected in the nucleus and/or signalization events mediated by these non-duplex structural features during miRNA biogenesis can determine the fate of the miRNA/miRNA* duplexes in separated AGO-loading processes.
期刊介绍：
Publishing the best original research papers in all key areas of modern plant biology from the world"s leading laboratories, The Plant Journal provides a dynamic forum for this ever growing international research community.
Plant science research is now at the forefront of research in the biological sciences, with breakthroughs in our understanding of fundamental processes in plants matching those in other organisms. The impact of molecular genetics and the availability of model and crop species can be seen in all aspects of plant biology. For publication in The Plant Journal the research must provide a highly significant new contribution to our understanding of plants and be of general interest to the plant science community.
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