Cell cycle-dependent proteolysis and ectopic overexpression of cyclin B1 in tobacco BY2 cells.
Activation of cyclin B/Cdc2 kinase complex triggers entry into mitosis in all eukaryotic cells. Although cyclin gene expression has been extensively studied in plants, not much is known at the level of the protein stability and function. Here, we demonstrated by using the highly synchronizable tobacco BY2 cell culture, that endogenous cyclin B1 protein undergoes cell cycle-dependent proteolysis and is stabilized when the spindle checkpoint has been activated. Furthermore, we established transgenic tobacco BY2 cell cultures expressing under the control of an inducible promoter, cyclin B1 protein as well as its non-degradable form as fusion proteins with GFP and found that the ectopic expression of these proteins did not dramatically disturb the cell cycle progression. These results indicate that, to a certain extent, cell cycle exit is possible without cyclin B1 proteolysis.
Criqui
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MC
Institut de Biologie Moléculaire des Plantes du CNRS, 12, rue du Général Zimmer, 67084 Strasbourg Cédex, France.
Parmentier
Y
Y
Derevier
A
A
Shen
W H
WH
Dong
A
A
Genschik
P
P
D002453:Cell Cycle; D002478:Cells, Cultured; D003001:Cloning, Molecular; D019926:Cyclin B / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D056744:Cyclin B1; D003546:Cysteine Endopeptidases / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D016195:G2 Phase; D049452:Green Fluorescent Proteins; D007976:Leupeptins / Q000494:pharmacology; D008164:Luminescent Proteins; D008938:Mitosis; D009097:Multienzyme Complexes / Q000378:metabolism; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D046988:Proteasome Endopeptidase Complex; D011494:Protein Kinases / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000166:cytology / Q000378:metabolism*
D019926:Cyclin B; D056744:Cyclin B1; D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D008164:Luminescent Proteins; D009097:Multienzyme Complexes; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D011494:Protein Kinases; C102333:histone H1 kinase; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde