Cell numbers and leaf development in Arabidopsis: a functional analysis of the STRUWWELPETER gene.
The struwwelpeter (swp) mutant in Arabidopsis shows reduced cell numbers in all aerial organs. In certain cases, this defect is partially compensated by an increase in final cell size. Although the mutation does not affect cell cycle duration in the young primordia, it does influence the window of cell proliferation, as cell number is reduced during the very early stages of primordium initiation and a precocious arrest of cell proliferation occurs. In addition, the mutation also perturbs the shoot apical meristem (SAM), which becomes gradually disorganized. SWP encodes a protein with similarities to subunits of the Mediator complex, required for RNA polymerase II recruitment at target promoters in response to specific activators. To gain further insight into its function, we overexpressed the gene under the control of a constitutive promoter. This interfered again with the moment of cell cycle arrest in the young leaf. Our results suggest that the levels of SWP, besides their role in pattern formation at the meristem, play an important role in defining the duration of cell proliferation.
Autran
Daphné
D
Laboratoire de Biologie Cellulaire, INRA, Route de Saint-Cyr, 78026 Versailles cedex, France.
Jonak
Claudia
C
Belcram
Katia
K
Beemster
Gerrit T S
GT
Kronenberger
Jocelyne
J
Grandjean
Olivier
O
Inzé
Dirk
D
Traas
Jan
J
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000502:physiology*; D002452:Cell Count; D002454:Cell Differentiation; D002455:Cell Division; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018398:Homeodomain Proteins / Q000502:physiology; D018519:Meristem / Q000166:cytology; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000166:cytology / Q000254:growth & development*; D012319:RNA Polymerase II / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D018749:RNA, Plant / Q000096:biosynthesis; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000502:physiology; D014158:Transcription, Genetic
C099055:AINTEGUMENTA protein, Arabidopsis; D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; C097496:STM protein, Arabidopsis; C469737:STRUWWELPETER protein, Arabidopsis; D014157:Transcription Factors; C116421:WUSCHEL protein, Arabidopsis; D012319:RNA Polymerase II