N-Myc shares cellular functions wiht c-Myc.
N-Myc is a member of the myc family of proto-oncogenes involved in initiation and progression of tumors. While c-MYC, the most characterized member of the family, is well known for its role in cellular proliferation and apoptosis, the function of N-MYC in differentiation and proliferation remains unclear. N-Myc mutant mice present a phenotype more consistent with a role of N-MYC protein in proliferation of precursor populations than in differentiation per se. Recent studies have also shown that N-MYC can enhance apoptosis and shorten the G1 phase of the cell cycle. However, the role of N-MYC in instigating cell-cycle progression has not been clearly demonstrated. Here, we demonstrate that overexpression of N-myc or activation of inducible N-MYC proteins is sufficient to induce apoptosis in serum-starved fibroblast cells, an effect that can be counteracted by overexpression of Bcl-2. Moreover, N-MYC can induce the reentry of quiescent cells into the cell cycle even in the absence of external stimuli. These results indicate that N-MYC and c-MYC share many properties, supporting the model that MYC-specific roles during embryonic development are mediated, at least in part, via their specific profile of expression rather than by their different protein functions.
Aubry
S
S
Centre de recherche en cancérologie de l'Université Laval, Centre Hospitalier Universitaire de Québec, Canada.
Charron
J
J
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D016895:Culture Media, Serum-Free; D003513:Cycloheximide / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D005347:Fibroblasts / Q000473:pathology; D016259:Genes, myc; D009955:Ornithine Decarboxylase / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics* / Q000378:metabolism*; D051381:Rats; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013629:Tamoxifen / Q000031:analogs & derivatives / Q000494:pharmacology; D015854:Up-Regulation
D016895:Culture Media, Serum-Free; D019253:Proto-Oncogene Proteins c-bcl-2; D016271:Proto-Oncogene Proteins c-myc; D011960:Receptors, Estrogen; D011994:Recombinant Proteins; D013629:Tamoxifen; C016601:afimoxifene; D004958:Estradiol; D003513:Cycloheximide; D009955:Ornithine Decarboxylase