Identification of three tomato flower and fruit MADS-box proteins with a putative histone deacetylase binding domain.
MADS-box transcription factors play crucial roles in organ and cell differentiation in organisms ranging from yeast to humans. Most of the work on plant MADS-box proteins focused on their roles in floral development whereas less information is available on their function in fruit maturation. We cloned three distinct tomato cDNAs using a RT-PCR approach, encoding LeMADS1, LeMADS5 and LeMADS6 factors and whose mRNAs mostly accumulate in tomato flowers and fruits. Phylogeny analysis indicates that LeMADS1, 5 and 6 belong to the MEF2-like family. When transiently expressed in tobacco leaves or in human cells, LeMADS1, 5 and 6 are targeted to the cell nucleus. As the endogenous target genes of these putative transcription factors are unknown, the transcriptional activity of these proteins was characterized in a heterologous system and we showed that, when fused to a Gal4-DNA-binding domain, they repress the transcription of heterologous reporter genes. Since histone deacetylases control MEF2 transcriptional activity and since a putative histone deacetylase binding site was present in LeMADS1, 5 and 6, we tested the potential interaction between these factors and HDAC5 deacetylase. Surprisingly, in this heterologous system, LeMADS1, 5 and 6 interacted with HDAC5 N-terminal region. Our data suggest that, like mammalian MEF2A, plant MADS-box transcriptional activity might be regulated by enzymes controlling chromatin acetylation.
Laboratoire Plaste et Différenciation Cellulaire, France. joel.gaffe@ujf-grenoble.fr
Joël
J
Gaffe
Claudie
C
Lemercier
Jean-Pierre
JP
Alcaraz
Marcel
M
Kuntz
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D017931:DNA Primers; D018744:DNA, Plant / Q000235:genetics / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000378:metabolism; D005091:Exons / Q000235:genetics; D035264:Flowers / Q000235:genetics* / Q000378:metabolism; D017343:Genes, Plant; D017930:Genes, Reporter; D006655:Histone Deacetylases / Q000235:genetics* / Q000378:metabolism; D007438:Introns / Q000235:genetics; D018551:Solanum lycopersicum / Q000235:genetics* / Q000378:metabolism; D026161:MADS Domain Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000302:isolation & purification; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D026161:MADS Domain Proteins; D010940:Plant Proteins; D018749:RNA, Plant; D006655:Histone Deacetylases