The TT8 gene encodes a basic helix-loop-helix domain protein required for expression of DFR and BAN genes in Arabidopsis siliques.
The TRANSPARENT TESTA8 (TT8) locus is involved in the regulation of flavonoid biosynthesis in Arabidopsis. The tt8-3 allele was isolated from a T-DNA-mutagenized Arabidopsis collection and found to be tagged by an integrative molecule, thus permitting the cloning and sequencing of the TT8 gene. TT8 identity was confirmed by complementation of tt8-3 and sequence analysis of an additional allele. The TT8 gene encodes a protein that displays a basic helix-loop-helix at its C terminus and represents an Arabidopsis ortholog of the maize R transcription factors. The TT8 transcript is present in developing siliques and in young seedlings. The TT8 protein is required for normal expression of two flavonoid late biosynthetic genes, namely, DIHYDROFLAVONOL 4-REDUCTASE (DFR) and BANYULS (BAN), in Arabidopsis siliques. Interestingly, TRANSPARENT TESTA GLABRA1 (TTG1) and TT2 genes also control the expression of DFR and BAN genes. Our results suggest that the TT8, TTG1, and TT2 proteins may interact to control flavonoid metabolism in the Arabidopsis seed coat.
Nesi
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N
Laboratoire de Biologie des Semences, Unité Mixte de Recherche INRA/INA-PG, Institut National de la Recherche Agronomique, Centre de Versailles, Route de Saint-Cyr, 78026 Versailles Cedex, France.
Debeaujon
I
I
Jond
C
C
Pelletier
G
G
Caboche
M
M
Lepiniec
L
L
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D003001:Cloning, Molecular; D016384:Consensus Sequence; D004269:DNA, Bacterial / Q000235:genetics; D019143:Evolution, Molecular; D005091:Exons; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018257:Helix-Loop-Helix Motifs; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics*
D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D004269:DNA, Bacterial; D010940:Plant Proteins; D014157:Transcription Factors; C036483:T-DNA; C417767:TT8 protein, Arabidopsis