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N-Myc shares cellular functions wiht c-Myc
1Centre de recherche en cancérologie de l'Université Laval, Centre Hospitalier Universitaire de Québec, Canada.
Abstract:
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.
Insights
The N-Myc proto-oncogene drives cell proliferation and can induce apoptosis, similar to c-MYC. Its expression profile, not protein function, likely dictates MYC
Area of Science:
- Oncology
- Molecular Biology
- Cell Biology
Background:
- N-Myc is a proto-oncogene implicated in tumor development.
- While c-MYC's roles in proliferation and apoptosis are known, N-MYC's functions are less understood.
- N-Myc mutant mice suggest a role in precursor cell proliferation.
Purpose of the Study:
- To clarify the role of N-MYC in cell-cycle progression and apoptosis.
- To investigate whether N-MYC shares functional similarities with c-MYC.
Main Methods:
- Overexpression of N-myc and inducible N-MYC proteins in serum-starved fibroblast cells.
- Utilizing Bcl-2 overexpression to counteract N-MYC effects.
- Assessing cell reentry into the cell cycle from quiescence.
Main Results:
- N-MYC overexpression induced apoptosis in serum-starved cells, an effect inhibited by Bcl-2.
- N-MYC promoted cell-cycle reentry from quiescence without external stimuli.
- N-MYC and c-MYC exhibit shared functional properties.
Conclusions:
- N-MYC actively promotes cell-cycle progression and can induce apoptosis.
- Shared functions between N-MYC and c-MYC suggest expression patterns mediate developmental roles.
- MYC family proto-oncogenes may have overlapping functions, with expression specificity driving distinct outcomes.