In vivo interference with AtTCP20 function induces severe plant growth alterations and deregulates the expression of many genes important for development.
AtTCP20 is a transcription factor belonging to the Arabidopsis (Arabidopsis thaliana) TCP-P subfamily, characterized by its capacity to bind to site II motifs (TGGGCY). Our aim was to understand the role of AtTCP20 in plant development. The expression pattern of a translational fusion of Prom(TCP20):CDS20GUSGFP suggested a function for AtTCP20 in several plant organs and stages of development. The role of AtTCP20 was challenged in planta by inducing expression of AtTCP20 proteins fused with either a transcriptional activator domain (VP16) or a repressor domain (EAR). Expression of both modified proteins led to severe developmental phenotypes. In-depth analysis suggested that AtTCP20 may participate in the regulation of cell expansion, cell division, and cell differentiation. Gene expression profiling in roots and hypocotyls revealed that 252 genes were down-regulated in both organs after induction of the AtTCP20EAR repressor gene. Site II motifs (TGGGCY) were underrepresented in their promoters. Conversely, GG(A/T)CCC sequences related to binding sites identified for TCP proteins in rice (Oryza sativa) were overrepresented, and a TCP20 fusion protein was shown to bind to these sequences in vitro. Gene ontology indicated that many targeted genes were involved in cell wall biogenesis and modification during expansion and also encoded numerous transcription factors controlling plant development. Our results are consistent with the previous proposal that AtTCP20 is involved in cell division and growth coordination. Moreover, they further suggest that AtTCP20 also contributes to cell expansion control and indicate a different involvement of this protein in plant morphogenesis depending on the organ and the developmental stage.
Hervé
Christine
C
Laboratoire des Interactions Plantes Microorganismes, INRA 441, 31326 Castanet Tolosan cedex, France.
Dabos
Patrick
P
Bardet
Claude
C
Jauneau
Alain
A
Auriac
Marie Christine
MC
Ramboer
Agnès
A
Lacout
Fabrice
F
Tremousaygue
Dominique
D
D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001483:Base Sequence; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D017405:Herpes Simplex Virus Protein Vmw65 / Q000378:metabolism; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D018517:Plant Roots / Q000166:cytology / Q000254:growth & development; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D029681:Arabidopsis Proteins; D017405:Herpes Simplex Virus Protein Vmw65; D018809:Proliferating Cell Nuclear Antigen; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C540502:TCP20 protein, Arabidopsis; D014157:Transcription Factors