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Restoration of Mga function to a Streptococcus pyogenes strain (M Type 50) that is virulent in mice
B Limbago1, K S McIver, V Penumalli
1Department of Microbiology and Immunology, Emory University Health Sciences Center, Atlanta, Georgia 30322, USA.
Abstract:
The Mga protein in B514Sm, a Streptococcus pyogenes strain isolated as a mouse pathogen, contains amino acid substitutions at conserved sites that render the protein defective. Replacement of mga50 with the functional homolog mga4.1 restored full expression of Mga-regulated proteins. Restoration of Mga function did not affect fibrinogen binding, nor did it affect virulence in several mouse models of group A streptococcus infection.
Insights
Defective Mga protein in Streptococcus pyogenes was restored using a functional homolog. This restoration did not impact fibrinogen binding or virulence in mouse infection models, suggesting Mga
Area of Science:
- Microbiology
- Molecular Biology
- Pathogenesis
Background:
- Streptococcus pyogenes Mga protein regulates virulence factors.
- Strain B514Sm exhibits a defective Mga protein due to amino acid substitutions.
Purpose of the Study:
- To investigate the functional consequences of defective Mga protein in Streptococcus pyogenes.
- To determine if restoring Mga function affects virulence and fibrinogen binding.
Main Methods:
- Genetic manipulation of Streptococcus pyogenes B514Sm.
- Replacement of the defective mga50 gene with a functional homolog (mga4.1).
- Assessment of Mga-regulated protein expression, fibrinogen binding, and mouse infection models.
Main Results:
- Replacement with mga4.1 restored full expression of Mga-regulated proteins.
- Restored Mga function did not alter fibrinogen binding.
- Restored Mga function did not affect virulence in mouse models of infection.
Conclusions:
- The defective Mga protein in strain B514Sm is functionally restored by introducing a functional homolog.
- Mga protein function is not essential for fibrinogen binding or virulence in the studied mouse models of Streptococcus pyogenes infection.