Plant Molecular Biology

, Volume 63, Issue 6, pp 777–785

The dsRNA-binding protein DRB4 interacts with the Dicer-like protein DCL4 in vivo and functions in the trans-acting siRNA pathway

  • Yukihiro Nakazawa
  • Akihiro Hiraguri
  • Hiromitsu Moriyama
  • Toshiyuki Fukuhara
Article

DOI: 10.1007/s11103-006-9125-8

Cite this article as:
Nakazawa, Y., Hiraguri, A., Moriyama, H. et al. Plant Mol Biol (2007) 63: 777. doi:10.1007/s11103-006-9125-8

Abstract

Arabidopsis thaliana encodes four Dicer-like (DCL) proteins and five dsRNA-binding (DRB) proteins. We have previously demonstrated that DCL4 specifically interacts with DRB4 in vitro. Here we describe the interaction between DCL4 and DRB4 in vivo. The phenotype of a mutant with a defect in DCL4 (dcl4-2) was similar to that of a mutant with a defect in DRB4 (drb4-1): both mutant plants had elongated and downwardly curled rosette leaves and over-accumulated anthocyanin. In immunoprecipitation experiments with either anti-DCL4 or anti-DRB4 antibody and crude extracts of wild-type Arabidopsis plants, co-immunoprecipitation of DCL4 and DRB4 was detected, indicating that DCL4 interacts with DRB4 in vivo. This interaction was confirmed by immunoprecipitation experiments using extracts from dcl4-2, drb4-1, or transgenic plants expressing the hemagglutinin-tagged version of DCL4 or DRB4. The results of immunoprecipitation experiments also suggest that most DCL4 is associated with DRB4, but that some DRB4 is free or associated with other proteins. Reduced accumulation of the TAS1 and TAS3trans-acting siRNA (ta-siRNA) and over accumulation of their target mRNAs (At5g18040 and auxin response factors ARF3 and ARF4) were detected in both drb4-1 and dcl4-2 mutants. These results indicate that DRB4, together with DCL4, functions in the ta-siRNA biogenesis.

Keywords

DCL4DicerDRB4dsRNA-binding proteinProtein–protein interactionta-siRNA

Abbreviations

ARF

Auxin response factor

ATA

Aurintricarboxylic acid

DCL

Dicer-like protein

DRB

dsRNA-binding protein

dsRBM

dsRNA-binding motif

dsRNA

Double-stranded RNA

GFP

Green fluorescent protein

GST

Glutathion S-transferase

HA

Hemagglutinin

HYL1

HYPONASTIC LEAVES1

LNA

Locked nucleic acid

miRNA

microRNAs

RNAi

RNA interference

siRNA

small interfering RNA

ta-siRNA

trans-acting siRNA

TRBP

TAR RNA-binding protein

WT

Wild-type

Supplementary material

11103_2006_9125_MOESM1_ESM.doc (58 kb)
ESM1 (DOC 58 kb)
11103_2006_9125_MOESM2_ESM.ppt (3.9 mb)
ESM2 (PPT 4,013 kb)

Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  • Yukihiro Nakazawa
    • 1
  • Akihiro Hiraguri
    • 1
  • Hiromitsu Moriyama
    • 1
  • Toshiyuki Fukuhara
    • 1
  1. 1.Department of Applied Biological SciencesTokyo University of Agriculture and TechnologyFuchu, TokyoJapan