Oncogenic truncation of the first repeat of c-Myb decreases DNA binding in vitro and in vivo.

Dini, Pouya; Lipsick, Joseph S.

doi:10.1128/mcb.13.12.7334

Cited by 71 publications

(82 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, the N-terminal domain of c-Myb, which v-Myb lacks, was required for activation of the ABCC3 gene, consistent with previous reports suggesting that the N-terminal domain of c-Myb could allow it to interact with additional promoters that are not recognized by v-Myb (Dini and Lipsick, 1993). However, our results showed that the other mutations in v-Myb also affected the activation of specific genes, and that no single mutation was responsible for the dramatic differences observed between v-Myb and c-Myb, suggesting that transcriptional specificity is a complex Figure 6.…”

Section: Discussionsupporting

confidence: 88%

Oncogenic mutations cause dramatic, qualitative changes in the transcriptional activity of c-Myb

et al. 2005

View full text Add to dashboard Cite

Section: Discussionsupporting

confidence: 88%

Oncogenic mutations cause dramatic, qualitative changes in the transcriptional activity of c-Myb

et al. 2005

View full text Add to dashboard Cite

“…We constructed a set of 17 alanine mutations that targeted (i) residues within the highly conserved DNA-binding domain that had previously been shown to be critical for DNA binding or for transcriptional regulation, (ii) residues within the highly conserved animal-specific C-terminal domain, and (iii) an acidic patch N-terminal to the DNA-binding domain that is present in all closely related Myb proteins of animals and that we have previously shown can regulate DNA binding in vitro and in vivo (5,(22)(23)(24)(25)(26)(27)(28)(29)(30) (Fig. 1).…”

Section: Evolutionarily Guided Alanine Substitution Mutants Of Drosopmentioning

confidence: 99%

“…Rather than targeting patches of highly charged residues that are likely to be exposed on the hydrophilic surface of a properly folded protein, we used multiple protein sequence alignments as a guide for identifying both charged and uncharged regions subject to evolutionarily guided alanine substitution. Our rationale was that because Drosophila Myb is present within the conserved Myb-MuvB or Drosophila Rb E2F and Myb-interacting (dREAM) multiprotein complex, some residues critical for protein function might be required for hydrophobic protein-protein interactions, protein-DNA interactions, or the creation of structural motifs or might be targets for posttranslational modifications (14-16).We constructed a set of 17 alanine mutations that targeted (i) residues within the highly conserved DNA-binding domain that had previously been shown to be critical for DNA binding or for transcriptional regulation, (ii) residues within the highly conserved animal-specific C-terminal domain, and (iii) an acidic patch N-terminal to the DNA-binding domain that is present in all closely related Myb proteins of animals and that we have previously shown can regulate DNA binding in vitro and in vivo (5,(22)(23)(24)(25)(26)(27)(28)(29)(30) (Fig. 1).…”

mentioning

confidence: 99%

Animal-specific C-terminal domain links myeloblastosis oncoprotein (Myb) to an ancient repressor complex

Andrejka

Wen

Ashton

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Members of the Myb oncoprotein and E2F-Rb tumor suppressor protein families are present within the same highly conserved multiprotein transcriptional repressor complex, named either as Myb and synthetic multivuval class B (Myb-MuvB) or as Drosophila Rb E2F and Myb-interacting proteins (dREAM). We now report that the animal-specific C terminus of Drosophila Myb but not the more highly conserved N-terminal DNA-binding domain is necessary and sufficient for (i) adult viability, (ii) proper localization to chromosomes in vivo, (iii) regulation of gene expression in vivo, and (iv) interaction with the highly conserved core of the MuvB/dREAM transcriptional repressor complex. In addition, we have identified a conserved peptide motif that is required for this interaction. Our results imply that an ancient function of Myb in regulating G2/M genes in both plants and animals appears to have been transferred from the DNA-binding domain to the animal-specific C-terminal domain. Increased expression of B-MYB/MYBL2, the human ortholog of Drosophila Myb, correlates with poor prognosis in human patients with breast cancer. Therefore, our results imply that the specific interaction of the C terminus of Myb with the MuvB/dREAM core complex may provide an attractive target for the development of cancer therapeutics.oncogene | transcription | repression | evolution T he Myb oncogene family was discovered because of the retroviral transduction of the chicken cellular myb protooncogene that generated the avian myeloblastosis virus (1, 2). Both the cellular Myb and viral Myb proteins are present within the nucleus of the cell, bind to specific DNA sequences, and can regulate gene expression (3-9). The Myb DNA-binding domain is present in members of all major classes of eukaryotic organisms, including plants, animals, fungi, cellular slime molds, and protists (10, 11). Simpler plants have only one or a few Myb transcription factors, whereas all flowering plant species have hundreds of related Myb transcription factors that arose via massive gene duplication and divergence (12). The picture in animals is simpler. All vertebrates have three closely related Myb transcription factors, whereas most invertebrates have only one Myb transcription factor. In addition to the presence of an aminoterminal Myb DNA-binding domain, most of these Myb transcription factors of animals share a conserved C-terminal domain that appears to be animal-specific. We have recently reported that, rather surprisingly, this C-terminal Myb domain is sufficient to rescue the lethality of a Myb null mutation in Drosophila when expressed via a heterologous promoter (13). We have now used a combination of genetic, cell biological, and biochemical approaches to explore the function of this animal-specific C-terminal Myb domain. We find that this domain is both necessary and sufficient for interaction with the synthetic multivulval class B (MuvB) core, a highly conserved transcriptional repressor complex that also interacts with the E2F-Rb tumor suppressor proteins (14-16...

show abstract

“…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).…”

mentioning

confidence: 99%

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

Heine¹,

Hernandez

Grotewold

2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

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...

show abstract

Oncogenic truncation of the first repeat of c-Myb decreases DNA binding in vitro and in vivo.

Cited by 71 publications

References 66 publications

Oncogenic mutations cause dramatic, qualitative changes in the transcriptional activity of c-Myb

Oncogenic mutations cause dramatic, qualitative changes in the transcriptional activity of c-Myb

Animal-specific C-terminal domain links myeloblastosis oncoprotein (Myb) to an ancient repressor complex

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

Contact Info

Product

Resources

About