Stochastic fluctuations and distributed control of gene expression impact cellular memory.

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Cellular processes are inherently noisy due to stochastic fluctuations.
• Cells maintain stable gene expression levels across generations, a phenomenon not fully understood.

Purpose of the Study:

• To investigate the role of mRNA and protein stability in maintaining stable gene expression levels over time.
• To understand how cellular epigenetic memory is transmitted to daughter cells.

Main Methods:

• Utilized a double reporter gene model in cell clones.
• Compared clones with stable mRNA/protein expression versus those with destabilized mRNA/protein expression.
• Employed computer simulations to analyze temporal dynamics of gene expression variation.

Main Results:

• Both stable and destabilized clones showed heterogeneity in reporter gene expression.
• Cells with stable gene products transmitted similar reporter protein levels to daughter cells.
• Short mRNA and protein half-lives led to complete suppression of epigenetic memory.

Conclusions:

• mRNA and protein stability are critical for conserving constant gene expression levels over multiple cell generations.
• Slow turnover of cellular components plays a significant role in maintaining a stable phenotype within a cellular lineage.