title: Specific regulation of c-myc oncogene expression in a murine B-cell lymphoma.
abstract: The c-myc oncogene has been implicated in a wide spectrum of B-cell neoplasias. In normal cells, the level of expression of the c-myc gene correlates with growth status. In the present study, we examined the effect of receptor-mediated inhibition of growth on c-myc expression in a B-cell lymphoma. The murine lymphoma line WEHI 231 has been characterized as an early B cell; it bears surface-bound IgM and has unrearranged c-myc genes. Following treatment of a WEHI 231 culture with anti-mouse Ig antiserum, the cells undergo one round of division and further proliferation is inhibited. We observed that this treatment specifically affected cytoplasmic levels of c-myc mRNA. An initial early increase is followed by a precipitous drop such that by 4 hr (after exposure) the amount of c-myc mRNA is below control values by a factor of approximately equal to 10. The drop in c-myc precedes cessation of DNA synthesis. During the 2- to 4-hr period, c-myc mRNA had a maximal half-life of between 20 and 30 min. In contrast, even 24 hr after anti-Ig exposure, the amounts of most major mRNAs, including mu heavy chain and actin, were not significantly altered. These results indicate that expression of an unrearranged c-myc gene can be selectively responsive to receptor-mediated regulatory events.
mesh_terms: D000818:Animals; D000936:Antigen-Antibody Complex; D001402:B-Lymphocytes / Q000276:immunology*; D002455:Cell Division; D002462:Cell Membrane / Q000276:immunology; D004261:DNA Replication; D007106:Immune Sera; D007136:Immunoglobulins / Q000276:immunology*; D008223:Lymphoma / Q000235:genetics / Q000276:immunology*; D051379:Mice; D009857:Oncogenes; D011061:Poly A / Q000235:genetics; D014176:Protein Biosynthesis; D012313:RNA / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D000936:Antigen-Antibody Complex; D007106:Immune Sera; D007136:Immunoglobulins; D012333:RNA, Messenger; D011061:Poly A; D012313:RNA