title: KETCH1 imports HYL1 to nucleus for miRNA biogenesis inArabidopsis.
abstract: MicroRNA (miRNA) is processed from primary transcripts with hairpin structures (pri-miRNAs) by microprocessors in the nucleus. How cytoplasmic-borne microprocessor components are transported into the nucleus to fulfill their functions remains poorly understood. Here, we report KETCH1 (karyopherin enabling the transport of the cytoplasmic HYL1) as a partner of hyponastic leaves 1 (HYL1) protein, a core component of microprocessor inArabidopsisand functional counterpart of DGCR8/Pasha in animals. Null mutation ofketch1is embryonic-lethal, whereas knockdown mutation ofketch1caused morphological defects, reminiscent of mutants in the miRNA pathway.ketch1knockdown mutation also substantially reduced miRNA accumulation, but did not alter nuclear-cytoplasmic shuttling of miRNAs. Rather, the mutation significantly reduced nuclear portion of HYL1 protein and correspondingly compromised the pri-miRNA processing in the nucleus. We propose that KETCH1 transports HYL1 from the cytoplasm to the nucleus to constitute functional microprocessor inArabidopsisThis study provides insight into the largely unknown nuclear-cytoplasmic trafficking process of miRNA biogenesis components through eukaryotes.
authors.affiliation: Department of Biochemistry and Biophysics, Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843.|Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Science, South China Normal University, Guangzhou 510631, China.
authors.forename: Zhonghui
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Biochemistry and Biophysics, Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843.|College of Horticulture, China Agricultural University, Beijing 100193, China.
authors.forename: Xinwei
authors.initials: X
authors.lastname: Guo
authors.affiliation: Department of Biochemistry and Biophysics, Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843.
authors.forename: Chunxiao
authors.initials: C
authors.lastname: Ge
authors.affiliation: Department of Biochemistry and Biophysics, Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843.
authors.forename: Zeyang
authors.initials: Z
authors.lastname: Ma
authors.affiliation: Department of Biochemistry and Biophysics, Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843.
authors.forename: Mengqiu
authors.initials: M
authors.lastname: Jiang
authors.affiliation: College of Horticulture, China Agricultural University, Beijing 100193, China.
authors.forename: Tianhong
authors.initials: T
authors.lastname: Li
authors.affiliation: Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Koiwa
authors.affiliation: Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea.
authors.forename: Seong Wook
authors.initials: SW
authors.lastname: Yang
authors.affiliation: Department of Biochemistry and Biophysics, Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843; xiuren.zhang@tamu.edu.
authors.forename: Xiuren
authors.initials: X
authors.lastname: Zhang
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D028884:Karyopherins; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D030821:Plants, Genetically Modified; D021381:Protein Transport; D012323:RNA Processing, Post-Transcriptional; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C420966:HYL1 protein, Arabidopsis; C000627109:KETCH1 protein, Arabidopsis; D028884:Karyopherins; D035683:MicroRNAs; D016601:RNA-Binding Proteins
keywords: HYL1; KETCH1; importin β; miRNA; pri-miRNA processing