Ordered origin of the typical two- and three-repeat Myb genes

Jiang, Cizhong; Gu, Jianying; Chopra, Surinder; Gu, Xun; Peterson, T.

doi:10.1016/j.gene.2003.09.049

Cited by 124 publications

(119 citation statements)

References 31 publications

(41 reference statements)

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“…R2R3-MYB proteins are specific to plants and are also the most abundant type in plants, with more than 100 R2R3-MYB members in the genomes of dicots and monocots (Jiang et al 2004a;Wilkins et al 2009). The three repeats of the prototypic MYB protein c-Myb are referred to as R1, R2 and R3, and repeats from other MYB proteins are named according to their similarity to R1, R2or R3 of c-Myb.…”

Section: Structure Of Mybmentioning

confidence: 99%

MYB transcription factor genes as regulators for plant responses: an overview

Ambawat

Sharma

Yadav

et al. 2013

Physiol Mol Biol Plants

818

544

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Regulation of gene expression at the level of transcription controls many crucial biological processes. Transcription factors (TFs) play a great role in controlling cellular processes and MYB TF family is large and involved in controlling various processes like responses to biotic and abiotic stresses, development, differentiation, metabolism, defense etc. Here, we review MYB TFs with particular emphasis on their role in controlling different biological processes. This will provide valuable insights in understanding regulatory networks and associated functions to develop strategies for crop improvement.

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Section: Structure Of Mybmentioning

confidence: 99%

MYB transcription factor genes as regulators for plant responses: an overview

Ambawat

Sharma

Yadav

et al. 2013

Physiol Mol Biol Plants

818

544

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“…The p1 gene encodes an R2R3 Myb-like transcription factor ( Jiang et al 2004). Expression of the p1 gene is observed predominantly in the floral organs, most notably the kernel pericarp and cob glumes.…”

mentioning

confidence: 99%

Gene Conversion Between Direct Noncoding Repeats Promotes Genetic and Phenotypic Diversity at a Regulatory Locus of Zea mays (L.)

Zhang

Peterson

2006

Genetics

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While evolution of coding sequences has been intensively studied, diversification of noncoding regulatory regions remains poorly understood. In this study, we investigated the molecular evolution of an enhancer region located 5 kb upstream of the transcription start site of the maize pericarp color1 (p1) gene. The p1 gene encodes an R2R3 Myb-like transcription factor that regulates the flavonoid biosynthetic pathway in maize floral organs. Distinct p1 alleles exhibit organ-specific expression patterns on kernel pericarp and cob glumes. A cob glume-specific regulatory region has been identified in the distal enhancer. Further characterization of 6 single-copy p1 alleles, including P1-rr (red pericarp/red cob) and P1-rw (red pericarp and white cob), reveals 3 distinct enhancer types. Sequence variations in the enhancer are correlated with the p1 gene expression patterns in cob glume. Structural comparisons and phylogenetic analyses suggest that evolution of the enhancer region is likely driven by gene conversion between long direct noncoding repeats ($6 kb in length). Given that tandem and segmental duplications are common in both animal and plant genomes, our studies suggest that recombination between noncoding duplicated sequences could play an important role in creating genetic and phenotypic variations.

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“…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.…”

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confidence: 99%

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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Ordered origin of the typical two- and three-repeat Myb genes

Cited by 124 publications

References 31 publications

MYB transcription factor genes as regulators for plant responses: an overview

MYB transcription factor genes as regulators for plant responses: an overview

Gene Conversion Between Direct Noncoding Repeats Promotes Genetic and Phenotypic Diversity at a Regulatory Locus of Zea mays (L.)

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

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