Related Experiment Videos
The v-mos and c-Ha-ras oncoproteins exert similar effects on the pattern of protein synthesis
R Klemenz1, S Hoffmann, R Jaggi
1Ludwig Institute for Cancer Research, Inselspital, Bern, Switzerland.
Abstract:
The effects of the ras and the mos oncogene products on the pattern of newly synthesized proteins was investigated in NIH3T3 cell lines. A conditional expression system which allowed hormonal induction of the oncogenes was utilized to detect effects on the accumulation of oncoproteins by two dimensional gel electrophoresis of crude cell extracts. Strong and reproducible changes of protein synthesis following the expression of the ras and mos oncogenes were detected. Transiently induced synthesis of four proteins with a molecular mass of 23 kDa, 32 kDa, 35 kDa, and 47 kDa was observed. These changes were qualitatively indistinguishable in both, ras and mos oncogene expressing cells. This is in agreement with the notion that the two oncogene products act on a common signal transduction pathway. Serum mediated growth induction of quiescent NIH3T3 cells led to a different pattern of altered protein synthesis. We observed the transient alteration in the synthesis rates of three proteins with a molecular mass of 27 kDa, 47 kDa and 52 kDa. Only the 47 kDa protein was also subject to regulation by the oncoproteins. One of the proteins whose synthesis was strongly induced by the ras and mos oncogene products is also expressed by heat shock.
Insights
The ras and mos oncogenes alter protein synthesis similarly in NIH3T3 cells, suggesting a shared signaling pathway. Growth signals induce distinct protein changes, with only one overlap.
Area of Science:
- Molecular Biology
- Cell Biology
- Oncogenesis
Background:
- The ras and mos proto-oncogenes are key regulators of cellular signaling pathways.
- Understanding their downstream effects on protein synthesis is crucial for cancer research.
Purpose of the Study:
- To investigate the impact of ras and mos oncogene expression on protein synthesis patterns in NIH3T3 cells.
- To compare the effects of oncogene activation with serum-mediated growth induction.
Main Methods:
- Utilized a conditional expression system for hormonal induction of ras and mos oncogenes.
- Employed two-dimensional gel electrophoresis to analyze newly synthesized proteins in cell extracts.
- Compared protein synthesis alterations induced by oncogenes versus serum growth factors.
Main Results:
- Ras and mos oncogene expression induced transient synthesis of four specific proteins (23, 32, 35, and 47 kDa).
- These oncogene-induced changes were qualitatively similar, supporting a common signaling pathway.
- Serum-mediated growth induction altered synthesis of three different proteins (27, 47, and 52 kDa), with only the 47 kDa protein overlapping with oncogene effects.
- One induced protein is also a heat shock protein.
Conclusions:
- Ras and mos oncogene products likely converge on a common signal transduction pathway.
- Oncogene-induced protein synthesis changes differ from those triggered by normal growth signals.
- The 47 kDa protein is a potential downstream target regulated by both oncogenic and growth factor signaling.