Molecular characterization of plant ubiquitin-conjugating enzymes belonging to the UbcP4/E2-C/UBCx/UbcH10 gene family.
The anaphase promoting complex or cyclosome is the ubiquitin-ligase that targets destruction box-containing proteins for proteolysis during the cell cycle. Anaphase promoting complex or cyclosome and its activator (the fizzy and fizzy-related) proteins work together with ubiquitin-conjugating enzymes (UBCs) (E2s). One class of E2s (called E2-C) seems specifically involved in cyclin B1 degradation. Although it has recently been shown that mammalian E2-C is regulated at the protein level during the cell cycle, not much is known concerning the expression of these genes. Arabidopsis encodes two genes belonging to the E2-C gene family (called UBC19 and UBC20). We found that UBC19 is able to complement fission yeast (Schizosaccharomyces pombe) UbcP4-140 mutant, indicating that the plant protein can functionally replace its yeast ortholog for protein degradation during mitosis. In situ hybridization experiments were performed to study the expression of the E2-C genes in various tissues of plants. Their transcripts were always, but not exclusively, found in tissues active for cell division. Thus, the UBC19/20 E2s may have a key function during cell cycle, but may also be involved in ubiquitylation reactions occurring during differentiation and/or in differentiated cells. Finally, we showed that a translational fusion protein between UBC19 and green fluorescent protein localized both in the cytosol and the nucleus in stable transformed tobacco (Nicotiana tabacum cv Bright Yellow 2) cells.
Criqui
Marie Claire
MC
Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, 12 rue du Général Zimmer, 67084 Strasbourg cedex, France.
de Almeida Engler
Janice
J
Camasses
Alain
A
Capron
Arnaud
A
Parmentier
Yves
Y
Inzé
Dirk
D
Genschik
Pascal
P
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D015139:Blotting, Southern; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins; D008025:Ligases / Q000235:genetics* / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D031224:Raphanus / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid; D044763:Ubiquitin-Conjugating Enzymes
D029681:Arabidopsis Proteins; D008164:Luminescent Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; C046288:ubiquitin carrier proteins; D049452:Green Fluorescent Proteins; C472233:UBC20 protein, Arabidopsis; C105156:UBE2C protein, human; D044763:Ubiquitin-Conjugating Enzymes; C106164:ubc11 protein, S pombe; D008025:Ligases; C472232:UBC19 protein, Arabidopsis