Transcriptional activation of the translocated c- myc oncogene in Burkitt lymphoma

Abstract

We have previously demonstrated that

Structure and expression of the oncogene c-myc in fresh tumor material from patients with hematopoietic malignancies.

“…DNA rearrangements and chromosomal translocations within and near to c-myc have been shown in several studies to be associated with elevated expression of c-myc in Burkitt's lymphoma cell lines (5,15,17,31). The (Fig.…”

“…An amplification of c-myc DNA has been found in HL60, a human promyelocytic leukemia cell line, and in primary leukemic cells from the same patient (10,13). In HL60, the level of myc RNA was shown to be elevated compared to other cell lines, presumably as a consequence of this gene amplification (39), but there is disagreement as to whether an elevated level of myc RNA accompanies the myc rearrangements seen in Burkitt's lymphoma and murine plasmacytoma (5,15,17,22,31,34,39).…”

Activation of a translocated human c-myc gene by an enhancer in the immunoglobulin heavy-chain locus

“…In these instances, the translocated gene is still transcribed 7,10,11,37 , whilst again the untranslocated gene may be silent 11,32,34 . In these cases, transcription of the translocated c-myc gene may be maintained by a cellular enhancer-type element yet to be identified,…”

An appraisal of the application of recombinant DNA techniques to chromosome defects

“…In the two cell lines examined that carried 2:8 translocations, it was found that the breakpoint on chromosome 8 had occurred distal to c-myc and that the gene had not been translocated. A similar experiment on an 8:14 translocation line supported the data of Erikson et al (1983), showing the translocation of c-myc to chromosome 14 (Dalla-Favera et al, 1982;Taub et al, 1982 involved in different stages of neoplasia (Diamond et al, 1983;Morton et al, 1984). Current research is focusing on how the c-myc gene becomes activated: this will provide valuable data for the study of similar systems.…”

“…The transcriptional activity of c-myc in a BL cell line has been examined directly; some authors report increased transcriptional activity Marcu et al, 1983) whereas others have found no significant change (Maguire et al, 1983;Westin et al, 1982;Shen-Ong et al, 1982). There is also evidence for heterogeneity in the breakpoint on chromosomes 8 and 14 (Dalla-Favera et al, 1982;Taub et al, 1982;Erikson et al, 1983). Hybridization in situ with a c-myc-specific probe has been used to examine the breakpoints in the 2:8 and 8:14 translocations (Davis et al, 1984); Dalla-Favera et al, 1982) in this powerful technique a radioactive probe sequence is hybridized directly against a metaphase spread.…”