Dataset Information

Farnesylated Heat Shock Protein 40 is a component of membrane-bound RISC in Arabidopsis

ABSTRACT: ARGONAUTE1 (AGO1) binds directly to small regulatory RNA and is a key effector protein of post-transcriptional gene silencing mediated by microRNA (miRNA) and small interfering RNA (siRNA). The formation of an RNA induced silencing complex (RISC) of AGO1 and small RNA requires the function of the Heat Shock Protein 70/90 chaperone system. Some functions of AGO1 occur in association with endomembranes, in particular the rough endoplasmic reticulum (rER), but proteins interacting with AGO1 in membrane fractions remain unidentified. In this study, we show that the farnesylated Heat Shock Protein 40 homologs, J2 and J3, associate with AGO1 in membrane fractions in a manner that involves protein farnesylation. We also show that three changes in AGO1 function are detectable in mutants in protein farnesylation and J2/J3. First, perturbations of the HSP40/70/90 pathway by mutation of j3, hsp90 and farnesyl transferase affect the amounts of AGO1 associated with membranes. Second, miRNA association with membrane-bound AGO1, and with membrane-bound polysomes is increased in farnesyl transferase and farnesylationdeficient J2/J3 mutants. Third, silencing by non-cell autonomously acting short interfering RNAs (siRNAs) is impaired. These observations highlight the involvement of farnesylated J2/J3 in small RNA-mediated gene regulation, and suggest that the importance of chaperone-AGO1 interaction is not limited to the RISC assembly process.

INSTRUMENT(S): Orbitrap Fusion

ORGANISM(S): Arabidopsis Thaliana (mouse-ear Cress)

TISSUE(S): Seedling

SUBMITTER: Franziska Voellmy

LAB HEAD: Peter Brodersen

PROVIDER: PXD010197 | Pride | 2018-09-10

REPOSITORIES: Pride

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			Action	DRS
	20141219_FS_FV_Brodersen_AGO1_crosslink.raw	Raw
	20141219_FS_FV_Brodersen_MOCK_crosslink.raw	Raw
	MaxQuantOutput.tar.gz	Other
	mockMaxQuantOutput.tar.gz	Other
	tables.pdf	Pdf

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Farnesylated heat shock protein 40 is a component of membrane-bound RISC in <i>Arabidopsis</i>.

Sjögren Lars L Floris Maïna M Barghetti Andrea A Völlmy Franziska F Linding Rune R Brodersen Peter P

The Journal of biological chemistry 20180907 43

ARGONAUTE1 (AGO1) binds directly to small regulatory RNA and is a key effector protein of post-transcriptional gene silencing mediated by microRNA (miRNA) and small interfering RNA (siRNA) in <i>Arabidopsis</i> The formation of an RNA-induced silencing complex (RISC) of AGO1 and small RNA requires the function of the heat shock protein 70/90 chaperone system. Some functions of AGO1 occur in association with endomembranes, in particular the rough endoplasmic reticulum (RER), but proteins interact ...[more]

PMID: 30194279

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Project description:Aim and experimental set-up: Sequencing of small RNA from total RNA fractions. The aim of this experiment was to compare profiles of miRNA expression between the following genetic backgrounds: Col-0 (wild type), era1-2 (farnesyl transferase mutant), j2-2/j3-2 + pJ3:J3 (j2/j3 double knockout expressing transgenic J3 under the control of the endogenous J3 promoter), j2-2/j3-2 + pJ3:J3C417S (j2/j3 double knockout expressing transgenic J3 mutated in the farnesylation site (C417S) under the control of the endogenous J3 promoter). Seedlings were grown under sterile conditions for 16 days. Two biological replicates of each genotype were harvested, and total RNA was prepared by Trizol extraction. Small RNA libraries were constructed using NEBNext Small RNA Library Prep Set and sequenced on an Illumina platform. Sequencing of small RNA bound to AGO1 in membrane fractions The aim of this experiment was to characterize AGO1-bound small RNAs in membrane fractions, and to answer two specific questions: Can miRNAs be identified whose association with membrane-bound AGO1 is different between the following four genotypes: Col-0 (wild type), era1-2 (farnesyl transferase mutant), j2-2/j3-2 + pJ3:J3 (j2/j3 double knockout expressing transgenic J3 under the control of the endogenous J3 promoter), j2-2/j3-2 + pJ3:J3C417S (j2/j3 double knockout expressing transgenic J3 mutated in the farnesylation site (C417S) under the control of the endogenous J3 promoter) Is the ratio between reads matching miRNA and miRNA* different between the above four genotypes? Seedlings were grown under sterile conditions for 16 days. Two biological replicates of each genotype were harvested. Microsomes were prepared from 2g of seedling tissue, solubilized by 1% deoxycholate and AGO1 was immunoprecipitated with specific antibodies (Agrisera). Immunopurified AGO1 was eluted from Protein A sepharose beads by competitive elution with antigenic AGO1 peptide. Small RNA was extracted by Trizol extraction from eluted AGO1. Small RNA libraries were constructed using NEBNext Small RNA Library Prep Set and sequenced on an Illumina platform.

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