The AtRbx1 protein is part of plant SCF complexes, and its down-regulation causes severe growth and developmental defects.
Recently in yeast and animal cells, one particular class of ubiquitin ligase (E3), called the SCF, was demonstrated to regulate diverse processes including cell cycle and development. In plants SCF-dependent proteolysis is also involved in different developmental and hormonal regulations. To further investigate the function of SCF, we characterized at the molecular level the Arabidopsis RING-H2 finger protein AtRbx1. We demonstrated that the plant gene is able to functionally complement a yeast knockout mutant strain and showed that AtRbx1 protein interacts physically with at least two members of the Arabidopsis cullin family (AtCul1 and AtCul4). AtRbx1 also associates with AtCul1 and the Arabidopsis SKP1-related proteins in planta, indicating that it is part of plant SCF complexes. AtRbx1 mRNAs accumulate in various tissues of the plant, but at higher levels in tissues containing actively dividing cells. Finally to study the function of the gene in planta, we either overexpressed AtRbx1 or reduced its expression by a dsRNA strategy. Down-regulation of AtRbx1 impaired seedling growth and development, indicating that the gene is essential in plants. Furthermore, the AtRbx1-silenced plants showed a reduced level of AtCul1 protein, but accumulated higher level of cyclin D3.
Lechner
Esther
E
Institut de Biologie Moléculaire des Plantes du CNRS, 12, rue du Général Zimmer, 67084 Strasbourg Cédex, France.
Xie
Daoxin
D
Grava
Sandrine
S
Pigaglio
Emmanuelle
E
Planchais
Severine
S
Murray
James A H
JA
Parmentier
Yves
Y
Mutterer
Jerome
J
Dubreucq
Bertrand
B
Shen
Wen-Hui
WH
Genschik
Pascal
P
D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000378:metabolism; D056743:Cyclin D3; D016213:Cyclins / Q000378:metabolism; D015536:Down-Regulation; D018507:Gene Expression Regulation, Developmental; D005816:Genetic Complementation Test; D005982:Glutathione Transferase / Q000378:metabolism; D006579:Heterozygote; D006801:Humans; D015151:Immunoblotting; D008025:Ligases / Q000096:biosynthesis* / Q000737:chemistry*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D030821:Plants, Genetically Modified; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D012330:RNA, Double-Stranded / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D019089:Stem Cell Factor / Q000378:metabolism; D014018:Tissue Distribution; D019076:Transgenes; D044767:Ubiquitin-Protein Ligases; D015003:Yeasts / Q000235:genetics
C534696:CCND3 protein, human; D018797:Cell Cycle Proteins; D056743:Cyclin D3; D016213:Cyclins; D012330:RNA, Double-Stranded; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D019089:Stem Cell Factor; D044767:Ubiquitin-Protein Ligases; D005982:Glutathione Transferase; D008025:Ligases