Yeast mating and image-based quantification of spatial pattern formation.

Area of Science:

• Cell Biology
• Biophysics
• Systems Biology

Background:

• Cell-to-cell communication is vital, often mediated by secreted signaling molecules.
• Visualizing extracellular signaling molecule gradients is challenging due to molecule size and experimental limitations.

Purpose of the Study:

• To develop and apply a novel method for estimating extracellular concentration profiles in vivo.
• To quantify pheromone (α-factor) and protease (Bar1) distributions in yeast mating populations.
• To understand the role of Bar1 in shaping pheromone gradients and influencing cell behavior.

Main Methods:

• Developed a method using spatiotemporal mathematical models derived from microscopic analysis.
• Applied the method to populations of thousands of haploid yeast cells during mating.
• Quantified extracellular distributions of α-factor and Bar1 activity.

Main Results:

• Bar1 limits pheromone signal range and is critical for establishing α-factor gradients essential for mating.
• Wild type yeast populations create spatial pheromone patterns influencing differential growth and mating, unlike BAR1 deletion strains.
• This effect is observed in high-density cultures, highlighting Bar1's role in population-level signaling.

Conclusions:

• Bar1 protease plays a significant role in regulating pheromone distribution within large yeast populations.
• Wild type populations exhibit higher mating efficiency and growth rates compared to mixed MATa bar1Δ/MATα cultures.
• Cells exploit rapidly diffusing molecules to gain spatial information, leading to distinct transcriptional programs and phenotypes.