Global phenotypic profiling identifies a conserved actinobacterial cofactor for a bifunctional PBP-type cell wall...

Area of Science:

• Microbiology
• Bacterial Morphogenesis
• Cell Biology

Background:

• Members of the Corynebacterineae suborder exhibit unique cell surface structures.
• Unlike most bacteria, they grow via tip-extension, suggesting distinct morphogenic pathways.

Purpose of the Study:

• To investigate the genetic basis of shared morphogenic mechanisms within the Corynebacterineae suborder.
• To identify novel genes involved in cell surface biogenesis and polar growth.

Main Methods:

• Genome-wide phenotypic profiling of Corynebacterium glutamicum using a high-density transposon mutant library.
• Transposon-sequencing (Tn-seq) to assess mutant fitness under various stress conditions, including antibiotic challenges.
• Bioinformatic analysis and clustering of phenotypic fingerprints to identify genes with significant roles.

Main Results:

• Identified several genes of previously unknown function involved in surface biogenesis.
• Discovered CofA (Cgp_0016) as a novel interaction partner of peptidoglycan synthase PBP1a.
• Demonstrated that CofA promotes stable accumulation of PBP1a at sites of polar growth.
• Found homologous interactions in Mycobacterium tuberculosis, indicating conserved mechanisms.

Conclusions:

• The study elucidates key genetic players in Corynebacterineae morphogenesis, particularly CofA's role in cell wall synthesis and polar growth.
• The findings provide insights into conserved bacterial growth principles relevant to clinically significant species like Mycobacterium tuberculosis.
• The generated dataset serves as a valuable resource for future research on bacterial cell surface architecture and development.