A host-vector system for heterologous gene expression in Streptococcus gordonii

Area of Science:

• Microbiology
• Molecular Biology
• Biotechnology

Background:

• Streptococcus gordonii (Sg) Challis is a commensal bacterium found in the human oral cavity.
• Heterologous gene expression in Sg is challenging.
• Surface display of antigens on Sg can be achieved using fusion partners like the M6 protein.

Purpose of the Study:

• To develop a novel host-vector system for efficient heterologous gene expression in Sg Challis.
• To facilitate the construction of translational gene fusions using the M6-protein-encoding gene (emm6).
• To enable the display of foreign antigens on the surface of Sg.

Main Methods:

• Development of a host-vector system based on chromosomal integration of plasmid insertion vectors.
• Utilizing the emm6 gene as a fusion partner for translational gene fusions.
• Engineering recipient host strains for efficient integration and surface display.

Main Results:

• The developed system achieved 100% transformant acquisition of drug-resistance markers and M6 molecule surface display.
• High-frequency chromosomal integration was observed in the recipient host GP1221.
• Transformation yielded a high number of transformants (8.1 X 10^5 per ml) with 1 microgram of insertion vector DNA.

Conclusions:

• The new host-vector system provides an efficient method for heterologous gene expression and surface display in Sg Challis.
• This system is valuable for applications requiring engineered Sg strains, such as vaccine development or probiotic delivery.
• The high efficiency of chromosomal integration and surface display makes this system robust for further research and development.