Redox Regulation of Plant Homeodomain Transcription Factors

Tron, Adriana E.; Bertoncini, Carlos W.; Chan, Raquel L.; González, Daniel H.

doi:10.1074/jbc.m203297200

Cited by 91 publications

(62 citation statements)

References 52 publications

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“…The regulation of protein activity by intracellular REDOX potential is a mechanism by which the activity of many proteins is regulated (18,(27)(28)(29)(30)(31)(32). Our results suggest the possibility that plant R2R3 MYB domain proteins are regulated in this fashion and that the presence of two closely positioned cysteine residues permits the formation of intramolecular disulfide bonds in non-reducing conditions that impair DNA binding.…”

Section: Discussionmentioning

confidence: 64%

Two Cysteines in Plant R2R3 MYB Domains Participate in REDOX-dependent DNA Binding

Heine¹,

Hernandez

Grotewold

2004

Journal of Biological Chemistry

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MYB DNA-binding domains are formed by one to three or more imperfect repeats (R1, R2, and R3) containing periodic tryptophan residues (1-3). Each MYB repeat is defined by ϳ50 amino acids that form three ␣-helices. The last two helices of each MYB repeat adopt a helix-turn-helix motif; the third helix of each MYB repeat is involved in the main DNA contacts (4). The vertebrate Myb genes, which include c-Myb, A-Myb, and B-Myb, encode proteins with MYB domains formed by three MYB repeats (R1R2R3 MYB). In contrast, the majority of plant Myb genes encode proteins with only two MYB repeats most similar to the vertebrate R2 and R3 MYB repeats (R2R3 MYB) (5-8). Plant R2R3 Myb genes are likely to have originated from an ancestral gene that is represented today by the B-Myb gene in vertebrates (6) and by the small pc-Myb (plant c-Myb) gene family in the plants (5). The evolutionary steps involved in the formation of the plant-specific R2R3 MYB domains from the broadly distributed R1R2R3 MYB domains involved the sequential i) loss of R1 to yield the "atypical R2R3 MYB domains," ii) replacement of the first tryptophan of R3 by a hydrophobic amino acid, and iii) insertion of a Leu residue between the second and third helices of R2, to give the "typical R2R3 MYB" domains (9) (Fig. 1A). The loss of R1 and the replacement of the Trp residue probably had only a moderate effect upon the DNA-binding properties of the MYB domain, based on studies carried out in animal R1R2R3 MYB proteins (4, 10, 11). In contrast, the insertion of the Leu residue in v-MYB, an oncogenic form of c-MYB containing only R2 and R3 (12), completely abolished binding to DNA (13). An extensive amplification of the R2R3 Myb gene family occurred within the plants 250 -400 million years ago (14), which resulted in Arabidopsis thaliana encoding 125 R2R3 Myb genes (8, 15) and maize and related monocots encoding more than 200 R2R3 Myb genes (14, 16). The amplification of the R2R3 Myb gene family in the plants provides a unique opportunity to understand how the evolutionary steps that shaped a family of transcription factors resulted in the functional differences displayed by these regulatory proteins throughout the plant kingdom.A residue that has remained completely conserved in plants, fungi, and animals during the evolution of MYB domains corresponds to a cysteine located in the DNA recognition helix of R2 (Cys-130 in c-MYB corresponding to Cys-53 in Fig. 1B). This cysteine was proposed to serve as a REDOX sensor in vertebrate MYB transcription factors, and mutations of this residue significantly impaired DNA binding and transcriptional activity of c- 18). The NMR structure of the R2R3 MYB domain of c-MYB indicated that Cys-130, the only cysteine present in c-MYB and related MYB factors from vertebrates, is included in the hydrophobic core, maintaining the three helices of R2 in an unbound conformation at room temperature (4). Consistent with this model, the replacement of Cys-130 for Ser in c-MYB resulted in the loss of DNA binding (18). It is interesting, howe...

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Section: Discussionmentioning

confidence: 64%

Two Cysteines in Plant R2R3 MYB Domains Participate in REDOX-dependent DNA Binding

Heine¹,

Hernandez

Grotewold

2004

Journal of Biological Chemistry

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“…The sequence CPSCE is similar to sequences found in thioredoxins and proteins with iron/sulfur clusters. This observation, together with its conserved location near the HD-Zip domain, suggests that it may function as a sensor of redox changes within the cell (Sessa et al, 1993b;Tron et al, 2002).…”

Section: Discussionmentioning

confidence: 95%

Isolation and characterization of two homeodomain leucine zipper genes from the dioecious plant Silene latifolia.

et al. 2003

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Homeodomain leucine zipper (HD-Zip) genes encode transcription factors that are characterized by both a homeodomain and a leucine zipper motif. Two HDZip genes were isolated from cDNA of the male flower bud of the dioecious plant Silene latifolia . The two isolated genes, SlHDL1 and SlHDL2 , encode proteins with the characteristics of HD-Zip transcription factors belonging to HD-Zip classes I and II, respectively. The expression patterns of SlHDL1 and SlHDL2 throughout the floral developmental stages were studied using real-time PCR and in situ hybridization. SlHDL1 is specifically expressed in the outermost layer of the anthers and gynoeciums with a patchy pattern in the inner layers, suggesting that the product of SlHDL1 plays a role in the early developmental stage of the epidermal tissues of these floral organs. Its expression pattern in the anthers and gynoeciums suggests an involvement in differentiation of the reproductive organs. On the other hand, real-time PCR revealed accumulation of SlHDL2 transcripts in the anther and pollen grains of the male flower. These results suggest that SlHDL1 and SlHDL2 regulate specific targets in restricted regions leading to floral organ differentiation in S . latifolia .

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“…Residues identical to those of the Arabidopsis HDG1 are indicated by dashes. Conserved Cyss implicated in redox regulation (Tron et al, 2002) are shaded. GenBank accession numbers are Y17898 (ZmOCL1) and AF172931 (PaHB1).…”

Section: Expression Profiles Of the Arabidopsis Hd-zip IV Genesmentioning

confidence: 99%

Characterization of the Class IV Homeodomain-Leucine Zipper Gene Family in Arabidopsis

et al. 2006

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The Arabidopsis (Arabidopsis thaliana) genome contains 16 genes belonging to the class IV homeodomain-Leucine zipper gene family. These include GLABRA2, ANTHOCYANINLESS2, FWA, ARABIDOPSIS THALIANA MERISTEM LAYER1 (ATML1), and PROTODERMAL FACTOR2 (PDF2). Our previous study revealed that atml1 pdf2 double mutants have severe defects in the shoot epidermal cell differentiation. Here, we have characterized additional members of this gene family, which we designated HOMEODOMAIN GLABROUS1 (HDG1) through HDG12. Analyses of transgenic Arabidopsis plants carrying the gene-specific promoter fused to the bacterial β-glucuronidase reporter gene revealed that some of the promoters have high activities in the epidermal layer of the shoot apical meristem and developing shoot organs, while others are temporarily active during reproductive organ development. Expression profiles of highly conserved paralogous gene pairs within the family were found to be not necessarily overlapping. Analyses of T-DNA insertion mutants of these HDG genes revealed that all mutants except hdg11 alleles exhibit no abnormal phenotypes. hdg11 mutants show excess branching of the trichome. This phenotype is enhanced in hdg11 hdg12 double mutants. Double mutants were constructed for other paralogous gene pairs and genes within the same subfamily. However, novel phenotypes were observed only for hdg3 atml1 and hdg3 pdf2 mutants that both exhibited defects in cotyledon development. These observations suggest that some of the class IV homeodomain-Leucine zipper members act redundantly with other members of the family during various aspects of cell differentiation. DNA-binding sites were determined for two of the family members using polymerase chain reaction-assisted DNA selection from random oligonucleotides with their recombinant proteins. The binding sites were found to be similar to those previously identified for ATML1 and PDF2, which correspond to the pseudopalindromic sequence 5′-GCATTAAATGC-3′ as the preferential binding site.

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Redox Regulation of Plant Homeodomain Transcription Factors

Cited by 91 publications

References 52 publications

Two Cysteines in Plant R2R3 MYB Domains Participate in REDOX-dependent DNA Binding

Two Cysteines in Plant R2R3 MYB Domains Participate in REDOX-dependent DNA Binding

Isolation and characterization of two homeodomain leucine zipper genes from the dioecious plant Silene latifolia.

Characterization of the Class IV Homeodomain-Leucine Zipper Gene Family in Arabidopsis

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