The tobacco A-type cyclin, Nicta;CYCA3;2, at the nexus of cell division and differentiation.
Although most of the components of the cell cycle machinery are conserved in all eukaryotes, plants differ strikingly from animals by the absence of a homolog of E-type cyclin, an important regulator involved in G1/S-checkpoint control in animals. By contrast, plants contain a complex range of A-type cyclins, with no fewer than 10 members in Arabidopsis. We previously identified the tobacco A-type cyclin Nicta;CYCA3;2 as an early G1/S-activated gene. Here, we show that antisense expression of Nicta;CYCA3;2 in tobacco plants induces defects in embryo formation and impairs callus formation from leaf explants. The green fluorescent protein (GFP)-Nicta;CYCA3;2 fusion protein was localized in the nucleoplasm. Transgenic tobacco plants overproducing GFP-Nicta;CYCA3;2 could not be regenerated from leaf disc transformation, whereas some transgenic Arabidopsis plants were obtained by the floral-dip transformation method. Arabidopsis plants that overproduce GFP-Nicta;CYCA3;2 showed reduced cell differentiation and endoreplication and a dramatically modified morphology. Calli regenerated from leaf explants of these transgenic Arabidopsis plants were defective in shoot and root regeneration. We propose that Nicta;CYCA3;2 has important functions, analogous to those of cyclin E in animals, in the control of plant cell division and differentiation.
Yu
Yu
Y
Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Université Louis Pasteur de Strasbourg, 67084 Strasbourg, France.
Steinmetz
Andre
A
Meyer
Denise
D
Brown
Spencer
S
Shen
Wen-Hui
WH
D016375:Antisense Elements (Genetics) / Q000235:genetics; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D002453:Cell Cycle / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology*; D048429:Cell Size; D046508:Culture Techniques; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D016213:Cyclins / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins; D006657:Histones / Q000235:genetics / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D014026:Nicotiana / Q000166:cytology / Q000196:embryology / Q000235:genetics*
D016375:Antisense Elements (Genetics); D016213:Cyclins; D006657:Histones; D008164:Luminescent Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D018844:Cyclin-Dependent Kinases