title: Auxin-dependent cell cycle reactivation through transcriptional regulation of Arabidopsis E2Fa by lateral organ boundary proteins.
abstract: Multicellular organisms depend on cell production, cell fate specification, and correct patterning to shape their adult body. In plants, auxin plays a prominent role in the timely coordination of these different cellular processes. A well-studied example is lateral root initiation, in which auxin triggers founder cell specification and cell cycle activation of xylem pole-positioned pericycle cells. Here, we report that the E2Fa transcription factor of Arabidopsis thaliana is an essential component that regulates the asymmetric cell division marking lateral root initiation. Moreover, we demonstrate that E2Fa expression is regulated by the LATERAL ORGAN BOUNDARY DOMAIN18/LATERAL ORGAN BOUNDARY DOMAIN33 (LBD18/LBD33) dimer that is, in turn, regulated by the auxin signaling pathway. LBD18/LBD33 mediates lateral root organogenesis through E2Fa transcriptional activation, whereas E2Fa expression under control of the LBD18 promoter eliminates the need for LBD18. Besides lateral root initiation, vascular patterning is disrupted in E2Fa knockout plants, similarly as it is affected in auxin signaling and lbd mutants, indicating that the transcriptional induction of E2Fa through LBDs represents a general mechanism for auxin-dependent cell cycle activation. Our data illustrate how a conserved mechanism driving cell cycle entry has been adapted evolutionarily to connect auxin signaling with control of processes determining plant architecture.
authors: Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium.
authors: Barbara
authors: B
authors: Berckmans
authors: Valya
authors: V
authors: Vassileva
authors: Stephan P C
authors: SP
authors: Schmid
authors: Sara
authors: S
authors: Maes
authors: Boris
authors: B
authors: Parizot
authors: Satoshi
authors: S
authors: Naramoto
authors: Zoltan
authors: Z
authors: Magyar
authors: Claire Lessa
authors: CL
authors: Alvim Kamei
authors: Csaba
authors: C
authors: Koncz
authors: Laszlo
authors: L
authors: Bögre
authors: Geert
authors: G
authors: Persiau
authors: Geert
authors: G
authors: De Jaeger
authors: Jiří
authors: J
authors: Friml
authors: Rüdiger
authors: R
authors: Simon
authors: Tom
authors: T
authors: Beeckman
authors: Lieven
authors: L
authors: De Veylder
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology*; D050684:E2F Transcription Factors / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D055786:Gene Knockout Techniques; D007210:Indoleacetic Acids / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D058526:Plant Vascular Bundle / Q000166:cytology / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation
chemical_list: D029681:Arabidopsis Proteins; D050684:E2F Transcription Factors; C496141:E2Fa protein, Arabidopsis; D007210:Indoleacetic Acids; C573049:LBD18 protein, Arabidopsis; C573050:LBD33 protein, Arabidopsis; D014157:Transcription Factors