MicroRNAs (miRNAs) are small regulatory RNAs that have important regulatory roles in numerous developmental and metabolic processes in most eukaryotes. In Arabidopsis, DICER-LIKE1 (DCL1), HYPONASTIC LEAVES 1, SERRATE, HUA ENHANCER1 and HASTY are involved in processingof primary miRNAs (pri-miRNAs) to yield precursor miRNAs (pre-miRNAs) and eventually miRNAs. In addition to these components, mRNA cap-binding proteins, CBP80/ABA HYPERSENSITIVE1 and CBP20, also participate in miRNA biogenesis. Here, we show that STABILIZED1 (STA1), an Arabidopsis pre-mRNA processing factor 6 homolog, is also involved in the biogenesis of miRNAs. Similar to other miRNA biogenesisdefective mutants, sta1-1 accumulated significantly lower levels of mature miRNAs and concurrently higher levels of pri-miRNAs than wild type. The dramatic reductions of mature miRNAs were associated with the accumulation of their target gene transcripts and developmental defects. Furthermore, sta1-1 impaired splicing of intron containing pri-miRNAs and decreased transcript levels of DCL1. These results suggest that STA1 is involved in miRNA biogenesis directly by functioning in pri-miRNA splicing and indirectly by modulating the DCL1 transcript level.
Bibliographical noteFunding Information:
The National Research Foundation of Korea by the Korean Government MEST [2011-0027376 to B.-h.L., 2012R1A1A2008826 to B.-h.L.]; Next-Generation BioGreen 21 Program, Rural Development Administration, Republic of Korea [PJ009104 to B.-h.L.]; Sogang University Research [201214003.01 to B.-h.L.]; UNIK research initiative of the Danish Ministry of Science, Technology and Innovation [09-065274 to S.W.Y.]; Chinese Academy of Sciences and National Institutes of Health Grants [R01GM070795 to J.-K.Z., R01GM059138 to J.-K.Z.]; USDA Grant [2008-35100-04518 to J.-K.Z.]; University of California at Riverside Initial Complement Fund and a United States Department of Agriculture hatch fund [CA-R-BPS-7754H to R.L.]. Funding for open access charge: National Research Foundation of Korea by the Korean Government MEST [2012R1A1A2008826 to B.-h.L.]
The authors thank laboratory members for helpful discussion and Brian Christopher King for helpful comments on the manuscript. S.W.Y. gratefully acknowledges support from Center for Synthetic Biology at University of Copenhagen and experimental equipment support from iNtRON Biotechnology, Inc. Korea.
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