RACK1 scaffold proteins influence miRNA abundance in Arabidopsis.
MicroRNAs (miRNAs) regulate plant development by post-transcriptional regulation of target genes. In Arabidopsis thaliana, DCL1 processes precursors (pri-miRNAs) to miRNA duplexes, which associate with AGO1. Additional proteins act in concert with DCL1 (e.g. HYL1 and SERRATE) or AGO1 to facilitate efficient and precise pri-miRNA processing and miRNA loading, respectively. In this study, we show that the accumulation of plant microRNAs depends on RECEPTOR FOR ACTIVATED C KINASE 1 (RACK1), a scaffold protein that is found in all higher eukaryotes. miRNA levels are reduced in rack1 mutants, and our data suggest that RACK1 affects the microRNA pathway via several distinct mechanisms involving direct interactions with known microRNA factors: RACK1 ensures the accumulation and processing of some pri-miRNAs, directly interacts with SERRATE and is part of an AGO1 complex. As a result, mutations in RACK1 lead to over-accumulation of miRNA target mRNAs, which are important for ABA responses and phyllotaxy, for example. In conclusion, our study identified complex functioning of RACK1 proteins in the Arabidopsis miRNA pathway; these proteins are important for miRNA production and therefore plant development.
Center for Plant Molecular Biology, University of Tübingen, 72076, Tübingen, Germany; Chemical Genomics Centre of the Max Planck Society, 44227, Dortmund, Germany; Max Planck Institute for Developmental Biology, 72076, Tübingen, Germany.
Corinna
C
Speth
Eva-Maria
EM
Willing
Stephanie
S
Rausch
Korbinian
K
Schneeberger
Sascha
S
Laubinger
D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism / Q000502:physiology*; D060565:Argonaute Proteins / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D035683:MicroRNAs / Q000096:biosynthesis / Q000378:metabolism*; D012322:RNA Precursors / Q000096:biosynthesis; D016601:RNA-Binding Proteins; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface / Q000502:physiology*; D000072099:Serrate-Jagged Proteins
C117457:AGO1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D060565:Argonaute Proteins; D002135:Calcium-Binding Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D035683:MicroRNAs; C515163:RACK1 protein, Arabidopsis; D012322:RNA Precursors; D016601:RNA-Binding Proteins; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface; C000606277:SE protein, Arabidopsis; D000072099:Serrate-Jagged Proteins
AGO1; Arabidopsis; RACK1; SERRATE; miRNA