Physical modeling of ribosomes along messenger RNA: Estimating kinetic parameters from ribosome profiling experiments...

Area of Science:

• Molecular Biology
• Biophysics
• Computational Biology

Background:

• Gene expression involves synthesizing proteins from DNA, with translation being a key step.
• Existing models often overlook messenger RNA (mRNA) degradation, requiring multiple experiments to determine kinetic rates.
• Ribo-sequencing (Ribo-seq) provides ribosome density data but needs complementary methods for comprehensive kinetic analysis.

Purpose of the Study:

• To develop a novel theoretical framework and experimental setup to model gene expression, incorporating mRNA degradation.
• To analytically solve a ballistic ribosome-mRNA interaction model, considering mRNA decay.
• To enable precise determination of all kinetic rates, including mRNA degradation, from a single experimental setup.

Main Methods:

• A ballistic model simulating ribosome movement along mRNA without excluded volume interactions was employed.
• mRNAs were categorized based on ribosome count (1-4) in a novel experimental setup.
• Analytical solutions for the ballistic model were derived for fixed ribosome numbers, analyzing degradation regimes.

Main Results:

• The proposed model analytically solves the ballistic transport of ribosomes on mRNA, accounting for degradation.
• The method demonstrates high sensitivity to the mRNA degradation rate.
• Integrating monosome and polysome Ribo-seq profiles allows for the determination of all kinetic rates.

Conclusions:

• This novel approach accurately models gene expression by incorporating mRNA degradation.
• The method allows for the precise quantification of translation kinetics and mRNA decay rates.
• The integrated Ribo-seq analysis provides a comprehensive understanding of gene expression dynamics.