ABL oncogene expression during erythroleukemia cell differentiation.
The translocation between chromosome 9 and chromosome 22 which creates the Philadelphia chromosome moves the ABL oncogene from its normal location on chromosome 9 and fuses it with a portion of the BCR gene on chromosome 22. This new BCR/ABL fusion gene generates a unique 8.7 kilobase (kb) RNA which codes for a new 210 kilodalton (kd, p210) protein which has a protein tyrosine kinase activity that is greatly increased in comparison to the normal ABL protein. The human K562 cell line was derived from a patient with CML, and serves as one model for the regulation of expression of the ABL and BCR/ABL genes. This study examines the expression of the BCR/ABL fusion gene and the normal ABL gene in relation to differentiation and changes in proliferative state. The expression of both the normal ABL transcripts and the BCR/ABL fusion transcript decrease approximately ten-fold when the cells are induced to differentiate with hemin. In contrast, expression of the MYC oncogene is unaffected by hemin-induced differentiation. The results suggest that both ABL and BCR/ABL expression vary in proportion to the differentiation of the cells, but minimally if at all as a function of the cells' proliferative state.
Leibowitz
D
D
Department of Medicine, Indiana University School of Medicine, Indianapolis 46200-5121.
Popenoe
D
D
Mears
J G
JG
Bank
A
A
Schaefer-Rego
K
K
D002454:Cell Differentiation; D002455:Cell Division; D016044:Fusion Proteins, bcr-abl / Q000235:genetics; D015870:Gene Expression; D016313:Genes, abl; D006801:Humans; D004915:Leukemia, Erythroblastic, Acute / Q000235:genetics* / Q000473:pathology; D012333:RNA, Messenger / Q000032:analysis; D014158:Transcription, Genetic
D012333:RNA, Messenger; D016044:Fusion Proteins, bcr-abl