Petunia hybrida genes related to the maize regulatory C1 gene and to animal myb proto‐oncogenes

Ávila, Julio; Nieto, Concha; Cañas, Luis A.; Benito, M. Isabel; Paz‐Ares, Javier

doi:10.1046/j.1365-313x.1993.03040553.x

Cited by 90 publications

(81 citation statements)

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“…By contrast, ATMYB1 shows higher homology to human c-MYB (59%; than does ATMYB2 (48%). The presente of severa1 conserved sequences outside the DNA binding domain has been reported in a number of plant MYB proteins (Marocco et al, 1989;Jackson et al, 1991;Avila et al, 1993;Leech et al, 1993). However, we could not find the conserved sequences in the C terminus outside the DNA binding domain of ATMYB2.…”

Section: Cloning and Sequence Analysis Of A Myb-related Gene From Aramentioning

confidence: 83%

“…Recently, myb-related genes have been reported in maize (Grotewold et al, 1991), barley (Marocco et al, 1989), Antirrhinum (Jackson et al, 1991), petunia (Avila et al, 1993), Arabidopsis (Oppenheimer et al, 1991;, and Physcomitrella (Leech et al, 1993). The barley myb homolog, Hvl, may be involved in regulation of genes of the anthocyanin biosynthetic pathway, as is the maize C7 gene.…”

Section: Introductionmentioning

confidence: 99%

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An Arabidopsis myb homolog is induced by dehydration stress and its gene product binds to the conserved MYB recognition sequence.

et al. 1993

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An Arabidopsis cDNA (Atmyb2) that contains a sequence that encodes a transcription factor, which is a homolog of MYB, was cloned from a cDNA library prepared from dehydrated Arabidopsis rosette plants. A gene (AtmybP) corresponding to the Atmyb2 cDNA was also cloned and its nucleotide sequence was determined. RNA gel blot analysis showed that the AtmybP mRNA was induced by dehydration and dísappeared upon rehydration. The Atmyb2 mRNA also accumulated upon salt stress and with the onset of treatment with abscisic acid. A Pglucuronidase reporter gene driven by the AtmybP promoter was induced by dehydration and salt stress in transgenic Arabidopsis plants. These observations indicate that AtmybP is responsive to dehydration at the transcriptional level. The putative protein (ATMYB2) encoded by AtmybP has 274 amino acids, a molecular m a s of 32 kD, and a putative DNA binding domain that shows considerable homology to plant MYB-related proteins, such as maize C1. A fusion protein that included ATMYBP was expressed in Escherichia coli, and it bound specifically to oligonucleotides that contained a consensus MYB recognition sequence (TAACTG), such as is found in the simian virus 40 enhancer and the maize bronze1 promoter. Binding was sequence specific, as indicated by a gel mobility shift experiment. These results suggest that a MYB-related transcription factor is involved in the regulation of genes that are responsive to water stress in Arabidopsis.

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Section: Cloning and Sequence Analysis Of A Myb-related Gene From Aramentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

An Arabidopsis myb homolog is induced by dehydration stress and its gene product binds to the conserved MYB recognition sequence.

et al. 1993

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“…For example, Petunia hybrida contains between 20 and 30 different Myb homologues (Avila et al 1993) and recently 14 different Myb related cDNAs were characterized in the tomato, Lycopersicon esculentum (Lin et al 1996). Unfortunately only a small subset of these has been sequenced.…”

Section: Introductionmentioning

confidence: 99%

Molecular Evolution of the Myb Family of Transcription Factors: Evidence for Polyphyletic Origin

1998

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Abstract. The Myb family of proteins is a group of functionally diverse transcriptional activators found in both plants and animals that is characterized by a conserved DNA-binding domain of approximately 50 amino acids. Phylogenetic analyses of amino acid sequences of this family of proteins portray very disparate evolutionary histories in plants and animals. Animal Myb proteins have diverged from a common ancestor, while plants appear related only within the DNA-binding domain. Results imply a pattern of modular evolution of the Myb proteins centering on the possession of a helix-turn-helix motif. Based on this it is suggested that Myb proteins are a polyphyletic group related only by a ''Myb-box'' DNA-binding motif.

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“…The common feature of Myb factors is the presence of a conserved domain consisting of imperfect repeats of 50 -53 amino acids, called "tryptophan clusters" because of the highly conserved tryptophan residues involved in stabilizing the structure of the DNA binding domain (1). In plants, myb genes are present as large families (6 -100 members) involved in the control of a wide range of biochemical pathways (2)(3)(4)(5)(6), including responses to biotic and abiotic stresses (7)(8)(9)(10)(11)(12)(13).…”

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confidence: 99%

The Product of the Rice myb7 Unspliced mRNA Dimerizes with the Maize Leucine Zipper Opaque2 and Stimulates Its Activity in a Transient Expression Assay

Locatelli

Bracale²,

Magaraggia³

et al. 2000

Journal of Biological Chemistry

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myb7 mRNA is present in rice in spliced and unspliced forms, splicing being enhanced by anoxia. The protein (Mybleu) encoded by the unspliced mRNA is composed of an incomplete Myb domain followed by a leucine zipper; however, it lacks canonical sequences for DNA binding, transcriptional activation, and nuclear localization. We show here that in transiently transformed tobacco protoplasts, Mybleu is able to enhance the transcriptional activity of the maize leucine zipper Opaque2 on its target b32 promoter. The Mybleu transactivation effect is strictly dependent on the presence of Opaque2 and is driven by Mybleu-Opaque2 heterodimers. Mybleu is located in the nucleus, both in rice and in transformed tobacco protoplasts. In rice, the protein is expressed in regions corresponding to undifferentiated cells of roots and coleoptiles. Therefore, myb7 mRNA encodes, depending on its splicing, two transcription factors belonging to separate classes. One of them, Mybleu, has novel structural characteristics, suggesting the existence of new mechanisms acting in the activation of transcription.Mybs are a family of transcription factors widely represented in viruses, insects, mammals, and plants. The common feature of Myb factors is the presence of a conserved domain consisting of imperfect repeats of 50 -53 amino acids, called "tryptophan clusters" because of the highly conserved tryptophan residues involved in stabilizing the structure of the DNA binding domain (1). In plants, myb genes are present as large families (6 -100 members) involved in the control of a wide range of biochemical pathways (2-6), including responses to biotic and abiotic stresses (7-13).Screening a cDNA library from anaerobically grown rice coleoptiles, we isolated myb7, a cDNA derived from a Mybencoding unspliced mRNA (8). Some features of myb7 sequence indicate that it may be post-transcriptionally regulated; in particular, two unspliced introns are present in positions that are conserved with respect to other plant myb genes. Both spliced and unspliced myb7 mRNAs are present in vivo (7).In aerobically grown rice roots, we observed a higher proportion of unspliced myb7 RNA, with respect to the spliced form. The spliced form is instead predominant in rice roots during anoxia, a stress situation that generally inhibits splicing (14). These data suggest that post-transcriptional regulation controls the ratio between myb7 unspliced and spliced forms (7). This hypothesis is supported by the observation that the 5Ј region of the first intron can direct the synthesis of an in-frame leucine zipper, a functional domain present in several transcription factors (15-18).The putative polypeptide encoded by the unspliced myb7 mRNA consists of an incomplete Myb domain followed by the leucine zipper: we therefore named it Mybleu. Mybleu does not have the characteristics of a functional transcription factor. Indeed, it should be unable to bind DNA because of the presence of an incomplete Myb repeat. Moreover, neither a putative transcriptional activator region nor a c...

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Petunia hybrida genes related to the maize regulatory C1 gene and to animal myb proto‐oncogenes

Cited by 90 publications

References 0 publications

An Arabidopsis myb homolog is induced by dehydration stress and its gene product binds to the conserved MYB recognition sequence.

An Arabidopsis myb homolog is induced by dehydration stress and its gene product binds to the conserved MYB recognition sequence.

Molecular Evolution of the Myb Family of Transcription Factors: Evidence for Polyphyletic Origin

The Product of the Rice myb7 Unspliced mRNA Dimerizes with the Maize Leucine Zipper Opaque2 and Stimulates Its Activity in a Transient Expression Assay

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