Functional consequences of reductive protein evolution in a minimal eukaryotic genome
Jason Jiang1, Rui Qu1, Maria Grigorescu1
1Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
Cell Reports
|September 24, 2025
Summary
Microsporidia parasites have significantly reduced protein lengths compared to yeast, impacting their functionality. This genomic reduction limits their ability to perform essential functions, even in simpler organisms like yeast.
Area of Science:
- Genomics
- Parasitology
- Cell Biology
Background:
- Microsporidia are obligate intracellular parasites known for their extremely compact genomes.
- Understanding the structural and functional consequences of microsporidian genome reduction is crucial for comprehending their parasitic lifestyle.
Purpose of the Study:
- To investigate the comparative genomics of microsporidia proteins in relation to their yeast orthologs.
- To determine the impact of protein reduction on the functional capabilities of microsporidian proteins.
Main Methods:
- Comparative genomic analysis of microsporidia and budding yeast proteins.
- Identification and measurement of protein domain and linker lengths.
- Yeast complementation assays to assess protein functionality.
Main Results:
- Microsporidian proteins are, on average, 21% shorter than their yeast counterparts due to reduced domain and linker lengths.
- A significant proportion (34%) of microsporidian orthologs have lost essential C-terminal residues, and 13 essential domains are lost per genome.
- Most microsporidian proteins failed to complement yeast orthologs, exhibiting a 3-fold lower complementation ability compared to Rozella allomycis orthologs.
Conclusions:
- Microsporidian proteins exhibit drastic length reductions, impacting their functional potential.
- These genomic reductions result in a diminished capacity for microsporidian proteins to function within a yeast cellular context.
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