Loss of amplification and appearance of a novel translocation site of the c-myc oncogene in HL-60 leukemia cells.
The chromosomal localization of c-myc sequences was determined by in situ hybridization in HL-60 cells (HL-60a) which contain an amplified c-myc locus and in an HL-60 subline (T-HL60) which has lost the amplification and has proportionately lower levels of c-myc RNA. While in HL-60a cells amplified c-myc sequences were found on the M3q+ marker chromosome, in T-HL60 cells one or few residual c-myc copies were found on a novel 4q+ marker chromosome. Comparative phenotypic analysis of HL-60a and T-HL60 cells show that the decrease in c-myc amplification/expression is not accompanied by changes in the malignant phenotype, namely in doubling time and clonogenic capability in semi-solid media. The significance of these results is discussed in the context of the role of c-myc amplification in the establishment and/or maintenance of the leukemic phenotype in HL-60 cells. In general, these results further underscore the utility of in situ hybridization analysis in identifying oncogene translocations which are not detectable by conventional karyotypic analysis.
Donti
E
E
Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, NY.
Lanfrancone
L
L
Pelicci
P G
PG
Birnie
G D
GD
Dalla-Favera
R
R
D002460:Cell Line; D002871:Chromosome Banding; D015342:DNA Probes; D005784:Gene Amplification; D016259:Genes, myc; D006801:Humans; D007621:Karyotyping; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D010641:Phenotype; D012333:RNA, Messenger / Q000235:genetics; D014178:Translocation, Genetic
D015342:DNA Probes; D012333:RNA, Messenger