Control of root growth and development by cyclin expression.
Root development is plastic, with post-embryonic organogenesis being mediated by meristems. Although cell division is intrinsic to meristem initiation, maintenance and proliferative growth, the role of the cell cycle in regulating growth and development is unclear. To address this question, we examined the expression of cdc2 and cye genes, which encode the catalytic and regulatory subunits, respectively, of cyclin-dependent protein kinases that control progression through the cell cycle. Unlike cdc2, which is expressed not only in apical meristems but also before lateral root initiation in quiescent, pericycle cells arrested in the G2 phase of the cell cycle, cyc1At transcripts accumulate specifically in dividing cells immediately before cytokinesis. Ectopic expression of cyc1At under the control of the cdc2aAt promoter in Arabidopsis plants markedly accelerates growth without altering the pattern of lateral root development or inducing neoplasia. Thus cyclin expression is a limiting factor for growth, which in turn drives indeterminate development of the root system.
Doerner
P
P
Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA.
Jørgensen
J E
JE
You
R
R
Steppuhn
J
J
Lamb
C
C
D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D016203:CDC2 Protein Kinase / Q000235:genetics; D002453:Cell Cycle / Q000502:physiology; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D018844:Cyclin-Dependent Kinases / Q000235:genetics*; D016213:Cyclins / Q000502:physiology*; D017403:In Situ Hybridization; D007210:Indoleacetic Acids / Q000494:pharmacology; D018517:Plant Roots / Q000254:growth & development*; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000378:metabolism
D016213:Cyclins; D007210:Indoleacetic Acids; D012333:RNA, Messenger; C030737:indoleacetic acid; D016203:CDC2 Protein Kinase; D018844:Cyclin-Dependent Kinases