Two basic-helix-loop-helix genes (MYC-146 and GL3) from Arabidopsis can activate anthocyanin biosynthesis in a white-flowered Matthiola incana mutant.
Basic helix-loop-helix (bHLH) proteins, similar to mammalian Myc transcription factors, regulate the anthocyanin biosynthetic pathway in both monocots and dicots. Two Arabidopsis bHLH genes, GLABRA3 (GL3) and MYC-146, encode proteins that are similar throughout the predicted amino acid sequence to R and DELILA, which regulate anthocyanin production in maize and snapdragon, respectively. Northern blot analysis indicates that MYC-146 is most highly expressed in flower buds and flowers. Expression of a MYC-146 cDNA from the CaMV 35S promoter was unable to complement the anthocyanin deficiency in a ttg1 mutant of Arabidopsis and resulted in no obvious phenotypic change in Columbia plants. However, transient expression of GL3 and MYC-146 upon microprojectile bombardment of petals of a white-flowered mutant of Matthiola incana was able to complement anthocyanin deficiency. The lack of anthocyanin-deficient Arabidopsis mutants mapping to the locations of GL3 and MYC-146 suggests that the two bHLH proteins may be partially redundant and overlap in function.
Ramsay
Nicola A
NA
Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
Walker
Amanda R
AR
Mooney
Mark
M
Gray
John C
JC
D000595:Amino Acid Sequence; D000872:Anthocyanins / Q000096:biosynthesis*; D029681:Arabidopsis Proteins / Q000235:genetics*; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D015152:Blotting, Northern; D019607:Brassicaceae / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics*; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D018257:Helix-Loop-Helix Motifs / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D030821:Plants, Genetically Modified; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000235:genetics*
D000872:Anthocyanins; D029681:Arabidopsis Proteins; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D002352:Carrier Proteins; D018744:DNA, Plant; D018749:RNA, Plant; D015534:Trans-Activators; C417284:GL3 protein, Arabidopsis; C473611:MYC2 protein, Arabidopsis