Related Experiment Videos
Entry of mRNA into polyribosomes during recovery from starvation in mouse sarcoma 180 cells
Abstract:
Starvation in mouse sarcoma 180 cells leads to a block in initiation of protein synthesis which results in the conversion of polysomes to 80-S ribosomes. The mRNA is released as nucleoprotein particles. Addition of nutrients to the starved cell causes the rapid uptake of the mRNA into large polysomal structures. The ribosomes enter these structures more gradually, without much effect on the sedimentation profile of the labeled mRNA. The results indicate that the stored mRNA in starved cells is readily available for uptake into polysomes. They also suggest that the mRNA may be binding to components other than ribosomes during the initial stages of polysome formation.
Insights
Starved sarcoma cells release mRNA, which is rapidly reincorporated into polysomes upon nutrient addition. This indicates stored mRNA is readily available for protein synthesis initiation.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Protein synthesis regulation is crucial for cellular function.
- Starvation induces cellular stress responses impacting translation.
- Polysomes are complexes of mRNA and ribosomes actively engaged in protein synthesis.
Purpose of the Study:
- To investigate the fate of messenger RNA (mRNA) during starvation and refeeding in mouse sarcoma cells.
- To elucidate the dynamics of polysome formation and mRNA availability post-starvation.
Main Methods:
- Cell culture of mouse sarcoma 180 cells.
- Induction of starvation and subsequent refeeding.
- Analysis of polysome profiles and mRNA localization using sedimentation techniques.
Main Results:
- Starvation caused polysomes to dissociate into 80-S ribosomes and released mRNA as nucleoprotein particles.
- Upon refeeding, mRNA was rapidly incorporated into large polysomal structures.
- Ribosome recruitment to mRNA was gradual and did not significantly alter mRNA sedimentation.
Conclusions:
- Stored mRNA in starved cells is readily accessible for polysome formation.
- mRNA may initially bind to non-ribosomal components during early polysome assembly.