Transcriptional and post-transcriptional mechanisms are responsible for the increased expression of c-myc protooncogene in lymphocytes from patients with systemic lupus erythematosus

Peripheral blood mononuclear cells (MNC) of patients with systemic lupus erythematosus (SLE) have increased expression of the c-myc protooncogene. The factors which are responsible for the accumulation of c-myc mRNA levels in SLE MNC, however, have not been determined. We have investigated the steady-state mRNA accumulation, nuclear transcription rate, rate of mRNA degradation as well as methylation status for the c-myc protooncogene in patients with SLE. Increased transcription rate of c-myc protooncogene and slow degradation rate of c-myc mRNA both appear to contribute to the accumulation of c-myc RNA in peripheral blood MNC of patients with SLE. Sitespecific methylation of the human c-myc protooncogene in patients with SLE does not differ from that of normal controls. These findings provide evidence for both transcriptional and post-transcriptional alterations of c-myc protooncogene expression in human SLE.