We report here that the expression of endogenous microRNAs （miRNAs） can be efficiently silenced in Arabi- dopsis thaliana （Arabidopsis） using artificial miRNA （amiRNA） technology. We demonstrate that an amiRNA d...We report here that the expression of endogenous microRNAs （miRNAs） can be efficiently silenced in Arabi- dopsis thaliana （Arabidopsis） using artificial miRNA （amiRNA） technology. We demonstrate that an amiRNA designed to target a mature miRNA directs silencing against all miRNA family members, whereas an amiRNA designed to target the stem-loop region of a miRNA precursor transcript directs silencing against only the individual family member targeted. Furthermore, our results indicate that amiRNAs targeting both the mature miRNA and stem-loop sequence direct RNA silencing through cleavage of the miRNA precursor transcript, which presumably occurs in the nucleus of a plant cell during the initial stages of miRNA biogenesis. This suggests that small RNA （sRNA）-guided RNA cleavage in plants occurs not only in the cytoplasm, but also in the nucleus. Many plant miRNA gene families have been identified via sequencing and bio- informatic analysis, but, to date, only a small tranche of these have been functionally characterized due to a lack of ef- fective forward or reverse genetic tools. Our findings therefore provide a new and powerful reverse-genetic tool for the analysis of miRNA function in plants.展开更多
文摘We report here that the expression of endogenous microRNAs （miRNAs） can be efficiently silenced in Arabi- dopsis thaliana （Arabidopsis） using artificial miRNA （amiRNA） technology. We demonstrate that an amiRNA designed to target a mature miRNA directs silencing against all miRNA family members, whereas an amiRNA designed to target the stem-loop region of a miRNA precursor transcript directs silencing against only the individual family member targeted. Furthermore, our results indicate that amiRNAs targeting both the mature miRNA and stem-loop sequence direct RNA silencing through cleavage of the miRNA precursor transcript, which presumably occurs in the nucleus of a plant cell during the initial stages of miRNA biogenesis. This suggests that small RNA （sRNA）-guided RNA cleavage in plants occurs not only in the cytoplasm, but also in the nucleus. Many plant miRNA gene families have been identified via sequencing and bio- informatic analysis, but, to date, only a small tranche of these have been functionally characterized due to a lack of ef- fective forward or reverse genetic tools. Our findings therefore provide a new and powerful reverse-genetic tool for the analysis of miRNA function in plants.
