Identification of the leukemogenic protein of avian myeloblastosis virus and of its normal cellular homologue.

Boyle, W J; Lipsick, J S; Reddy, E. S. P.; Baluda, M A

doi:10.1073/pnas.80.10.2834

Cited by 82 publications

(73 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, an inframe termination codon occurs just 5' of the splice acceptor site for the ®rst captured exon. As a result, the 48 kDa-v-Myb protein is produced by a subgenomic spliced viral mRNA that fuses the ®rst six codons of the gag gene in-frame to 371 codons of vmyb (Boyle et al, 1983;. The 3' cellular/viral recombination event occurred within an exon of c-myb, resulting in a fusion of the last eleven codons of the env gene in-frame with v-myb.…”

Section: The Virusesmentioning

confidence: 99%

“…The proteins (Figure 1) The 48 kDa v-Myb protein encoded by AMV, the 135 kDa Gag-Myb-Ets protein encoded by the E26 virus, and the 75 kDa c-Myb protein are all nuclear and bind to the same DNA sequence (AACNG) (Biedenkapp et al, 1988;Boyle et al, 1983Boyle et al, , 1984Klempnauer et al, , 1984Klempnauer and Sippel, 1987). The sequence that de®nes the Myb family of proteins is an approximately 50 amino acid motif with a series of conserved residues including three tryptophans separated by a characteristic spacing (reviewed in Lipsick, 1996).…”

Section: The Virusesmentioning

confidence: 99%

See 1 more Smart Citation

Transformation by v-Myb

1999

View full text Add to dashboard Cite

Section: The Virusesmentioning

confidence: 99%

Section: The Virusesmentioning

confidence: 99%

Transformation by v-Myb

1999

View full text Add to dashboard Cite

“…The nucleotide sequence of v-myb represents a partial copy of a cellular gene, c-myb, and has been transduced into the viral genome from a chicken host (3,4,6,11,12). The viral gene encodes a 45,000-Mr protein, p45v-m b (1,7), which in turn is a truncated version of the 75,000-Mr protein (p75cn`yb) encoded by chicken c-myb (7). Both proteins are located in the cell nucleus (8), but the means by which p45v-,n,b elicits oncogenic transformation and the function of its cellular counterpart, p75c-l,'b, remain obscure.…”

mentioning

confidence: 99%

Transformation-defective mutant of avian myeloblastosis virus that is temperature sensitive for production of transforming protein p45v-myb.

Moscovici¹,

Klempnauer²,

Symonds³

et al. 1985

Mol. Cell. Biol.

View full text Add to dashboard Cite

We have characterized a mutant of avian myeloblastosis virus (strain GA907/7) that shows a reduced capacity to transform myelomonocytic cells at the nonpermissive temperature. Myelobiasts transformed by this mutant suffer a substantial decrease in the amount of the transforming protein p45v-myb when shifted from the permissive to the nonpermissive temperature. We presume that the 5-to 10-fold decrease in the amount of p45vmyb causes the loss of the transformed phenotype. The decrease is due to a reduction in the level of v-myb mRNA. Mutant GA907/7 thus provides genetic evidence that p45vmYb is the transforming protein of avian myeloblastosis virus and apparently represents an unusual defect in the production or stability of mRNA.Oncogenic transformation of myelomonocytic cells by avian myeloblastosis virus (AMV) is thought to be mediated by the expression of a viral oncogene termed v-myb (2, 5). The nucleotide sequence of v-myb represents a partial copy of a cellular gene, c-myb, and has been transduced into the viral genome from a chicken host (3,4,6,11,12). The viral gene encodes a 45,000-Mr protein, p45v-m b (1, 7), which in turn is a truncated version of the 75,000-Mr protein (p75cn`yb) encoded by chicken c-myb (7). Both proteins are located in the cell nucleus (8), but the means by which p45v-,n,b elicits oncogenic transformation and the function of its cellular counterpart, p75c-l,'b, remain obscure.Analysis of transformation-defective, temperaturesensitive mutants of oncogenic retroviruses has yielded valuable information about possible mechanisms of cell transformation. We have recently described a temperaturesensitive mutant of AMV (strain GA907/7, designated tsAMV hereafter), which shows a markedly reduced capacity to transform myeloid cells at the nonpermissive temperature (10). The results presented in this communication extend the characterization of this mutant to a biochemical analysis of viral mRNA and p45vni1b in cells transformed by tsAMV.The experiments to be described were all performed with a myeloblast cell line (GA950/2) that was derived by transforming chicken yolk sac macrophages with tsAMV (10). Cells of this line were cultivated in BT88 medium (9) supplemented with 10% tryptose phosphate broth, 5% calf serum, 5% chicken serum, and 1.6 ,ug of folic acid per ml. At the permissive temperature of 35.5°C, these cells proliferate and exhibit a blastlike morphology; when shifted to the nonpermissive temperature of 41°C, they cease to proliferate and attain a macrophagelike morphology within 2 to 5 days. * We first analyzed the level of p45v-,n,b at the permissive and nonpermissive temperatures by labeling with [35S]methionine. Myeloblasts transformed by tsAMV were incubated for 30 min in growth medium lacking methionine at either 35.5°C or 41°C (Fig. 1A). [35S]methionine (>600 Ci/mmol; Amersham Corp.) was then added to a final concentration of 500 ,uCi/ml, and the incubation was continued for 1 h at both temperatures. Cell lysates were prepared as described previously (7). Proteins of inter...

show abstract

“…These cells expressed v-myb, the oncogene of AMV, producing a 45,000-molecular-weight protein termed p45vmY (8,21 shown previously for other cell types (2, 11) this fluorescence was nuclear. By using anti-myc serum, it was found that approximately 80% of the cells exhibited nuclear fluorescence before cloning and 90 to 100% exhibited nuclear fluorescence after cloning (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The cellular genes from which the viral oncogenes v-myb and v-myc were derived have been termed c-myb and c-myc, respectively (4,9). Both c-myb and c-myc have been found to be expressed in hematopoietic cells, c-myb primarily in immature hematopoietic cells and c-myc in dividing hematopoietic cells and in a variety of other proliferating cells such as fibroblasts and B-lymphocytes (4,8,12,16,17,(20)(21)(22). In normal chicken and mouse myelomonocytic cells, the expression of both cellular genes appears to decrease as the cells become more differentiated (10,12,16,17,35,36).…”

mentioning

confidence: 99%

Coordinate regulation of myelomonocytic phenotype by v-myb and v-myc.

Symonds¹,

Klempnauer²,

Snyder³

et al. 1986

Mol. Cell. Biol.

View full text Add to dashboard Cite

Both avian myeloblastosis virus (by the action of v-myb) and avian myelocytomatosis virus MC29 (by the action of v-myc) transform cells of the myelomonocytic lineage. Whereas avian myeloblastosis virus elicits a relatively immature phenotype, cells transformed by MC29 resemble mature macrophages. When cells previously transformed by v-myb were superinfected with MC29, their phenotype was rapidly altered to that of a more mature cell. These superinfected cells expressed both v-myb (at a level similar to that found before superinfection) and v-myc. It therefore appears that the expression of v-myc can elicit certain properties of a more differentiated phenotype. In addition, unlike cells transformed by v-myb alone, the cells expressing both v-myb and v-myc could not be induced by the tumor promoter 12-0-tetradecanoylphorbol-13-acetate to differentiate to fully mature macrophages. Cells with a morphology similar to that of the superinfected cells were elicited by simultaneously infecting yolk sac macrophages with avian myeloblastosis virus and MC29. Such cells expressed both v-myb and v-myc. These results indicate that expression of v-myb and v-myc in infected cells coordinately regulates myelomonocytic phenotype and that the two viral oncogenes vary in their ability to interfere with tumor promoter-induced differentiation. Our findings also sustain previous suggestions that the oncogenes v-myb and v-myc may not transform target cells by simply blocking differentiation.

show abstract

Identification of the leukemogenic protein of avian myeloblastosis virus and of its normal cellular homologue.

Cited by 82 publications

References 34 publications

Transformation by v-Myb

Transformation by v-Myb

Transformation-defective mutant of avian myeloblastosis virus that is temperature sensitive for production of transforming protein p45v-myb.

Coordinate regulation of myelomonocytic phenotype by v-myb and v-myc.

Contact Info

Product

Resources

About