Septin Defects Favour Symmetric Inheritance of the Budding Yeast Deceptive Courtship Memory

Area of Science:

• Cell Biology
• Genetics
• Molecular Biology

Background:

• Mnemons are prion-like elements encoding cellular memory of past adaptations.
• Whi3 mnemon (Whi3^mnem) in yeast establishes a mating pheromone refractory state in mother cells.
• Whi3^mnem confinement relies on endoplasmic reticulum association and bud neck diffusion barriers.

Purpose of the Study:

• Investigate inheritance patterns of cellular memory during yeast cell division.
• Examine the role of cytokinesis and cell division defects in mnemon inheritance.
• Understand how Whi3^mnem confinement is affected by the first cell division post-adaptation.

Main Methods:

• Microscopy to observe Whi3^mnem localization and cell morphology.
• Analysis of septin protein localization during cell division.
• Assessment of endoplasmic reticulum membrane diffusion barriers.

Main Results:

• The first cell division after establishing pheromone refractoriness shows larger daughter cells and cytokinesis defects.
• Aberrant septin localization and weakened endoplasmic reticulum diffusion barriers are observed.
• These defects are specific to the first division and not seen in subsequent divisions.

Conclusions:

• Cytokinesis defects during prolonged cell division can disrupt mnemon inheritance.
• Altered confinement of Whi3^mnem impacts cellular memory transmission to daughter cells.
• Cell division dynamics play a crucial role in epigenetic inheritance of cellular adaptations.