Aberrant c-myc RNAs of Burkitt's lymphoma cells have longer half-lives.

Abstract

Communicated by W.Doerfler BL67 and BL18 are Burkitt's lymphoma cell lines with t(8;14) translocations (the breakpoint is in the first exon and first intron, respectively) in which the A-heavy chain switch region is fused to the c-myc gene in head to head orientation. In both cell lines only aberrant c-myc RNAs are found. BL67 cells contain two c-myc RNA species of 2.4 and 3.5 kb. The 2.4-kb RNA is initiated at several cryptic promoters in the first intron. The 3.5-kb RNA is transcribed from the immunoglobulin heavy chain anti-sense strand across the breakpoint of the translocation into the first exon of the c-myc gene and is then normally spliced using the physiological splice donor and acceptor sites of the c-myc gene. BL18 contains c-myc RNA of 2.4 kb initiated at cryptic promoters in the first intron and additional RNAs of 0.90 kb and 0.74 kb transcribed from the dual c-myc promoters on the reciprocal fragment of the translocation. The cytoplasmic turnover of these RNAs differs significantly from that of the normal c-myc message. The 3.5-kb RNA of BL67 cells and the 0.90-kb and 0.74-kb RNAs of BL18 cells, which are both hybrid molecules consisting of c-myc and immunoglobulin sequences, have a halflife of several hours in contrast to the normal c-myc message with a half-life of 15 min. The aberrant 2.4-kb c-myc RNAs of BL67 and BL18 cells are also more stable than the normal c-myc message and disappear with a half-life of 50 min. The results are compatible with the model that the secondary structure of the normal c-myc RNA is required for the fast, regulated decay of the c-myc message in the cytoplasm.

Cloning and functional analysis of the hematopoietic cell‐specific phospholipase Cγ2 promoter

“…4A). The rapid decrease of c-myc RNA with a half life of less than 0.5 h upon addition of actinomycin D confirmed earlier reports [26,27]. In contrast, the PLCg RNA, even though expressed at low levels, was very stable and showed no decrease of steady-state levels during the time course of the experiment.…”

MYC oncogenes and human neoplastic disease

“…However, the actual alterations which are responsible for this phenomenon were not identi®ed (Eick et al, 1985).…”

Transcriptional down-regulation of c-myc in human prostate carcinoma cells by the synthetic androgen mibolerone

“…RNA derived from promoter P1 and P. directly visualised by a uniformly labelled. single-stranded SmaI-PvuII probe (probe a, Figure 1 (Eick et al, 1985).…”