Unraveling adaptive evolution: how a single point mutation affects the protein coregulation network.

Area of Science:

• Evolutionary biology
• Molecular evolution
• Microbial genetics

Background:

• Understanding adaptive evolution necessitates identifying the molecular underpinnings of pleiotropic mutation effects.
• Pleiotropy, where a single gene influences multiple traits, is a key factor in evolutionary processes.

Purpose of the Study:

• To characterize the pleiotropic effects of an adaptive mutation on protein levels in Pseudomonas fluorescens SBW25.
• To investigate the molecular basis and network-level consequences of adaptive mutations.

Main Methods:

• Proteomic analysis of Pseudomonas fluorescens SBW25 after acquiring a specific adaptive mutation.
• Identification and quantification of protein level changes using mass spectrometry.
• Analysis of protein associations within coregulatory networks.

Main Results:

• An adaptive single-base pair substitution resulted in 52 proteomic changes affecting 46 identified proteins.
• None of the altered proteins were essential for the adaptive phenotype itself.
• Affected proteins were primarily involved in metabolic pathways linked to fitness-reducing effects of the mutation.
• The mutation rewired a coregulatory network, altering protein relationships.

Conclusions:

• Adaptive mutations can have extensive, pleiotropic effects on cellular proteomes.
• These effects often involve metabolic pathways and can lead to antagonistic fitness consequences.
• The rewiring of coregulatory networks by mutations provides a molecular mechanism for pleiotropy in evolution.