A point mutation in the DNA binding domain of the v-myb oncogene of E26 virus confers temperature sensitivity for transformation of myelomonocytic cells.
We have molecularly cloned a mutant of the v-myb, ets-containing E26 avian leukemia virus which is temperature sensitive for the transformation of myeloid cells. Cells infected with this mutant, ts21E26, are immature at 37 degrees C and can be induced to differentiate into resting, macrophage-like cells when shifted to 42 degrees C. The sequence of ts21E26 reveals a single relevant nucleotide alteration resulting in a threonine to arginine change in the highly conserved, putative DNA binding v-myb portion of the p135gag-myb-ets protein. Surprisingly, a ts21E26 viral construct in which the v-ets gene domain was deleted was only weakly temperature sensitive, although temperature sensitivity was largely restored in another v-ets deletion mutant whose 3' terminal sequences were replaced with those from the AMV v-myb gene. These results suggest that the temperature sensitive lesion in v-myb of ts21E26 alters the DNA binding capacity of p135 at 42 degrees C and that the primary structure of the C-terminus of this protein has an influence on the activity of sequences that are further upstream.
Frykberg
L
L
Differentiation Programme, European Molecular Biology Laboratory, Heidelberg, Federal Republic of Germany.
Metz
T
T
Brady
G
G
Introna
M
M
Beug
H
H
Vennström
B
B
Graf
T
T
D000818:Animals; D001120:Arginine; D001354:Avian Leukosis Virus; D001483:Base Sequence; D002454:Cell Differentiation; D002455:Cell Division; D002472:Cell Transformation, Viral; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics*; D015479:Leukemia, Myelomonocytic, Acute / Q000209:etiology / Q000235:genetics*; D009154:Mutation; D009856:Oncogene Proteins, Viral / Q000235:genetics*; D010641:Phenotype; D013329:Structure-Activity Relationship; D013696:Temperature
D004268:DNA-Binding Proteins; D009856:Oncogene Proteins, Viral; D001120:Arginine