A yeast intron as a translational terminator in a plasmid shuttle vector

Area of Science:

• Molecular Biology
• Yeast Genetics
• Recombinant DNA Technology

Background:

• Plasmid shuttle vectors are essential for molecular biology, enabling DNA manipulation in Escherichia coli (E. coli) before transformation into other hosts.
• Existing vectors like pCWK1 for Kluyveromyces lactis (K. lactis) use the LAC4 promoter, which is tightly regulated in yeast but constitutively active in E. coli.
• Constitutive expression of heterologous genes in E. coli can lead to toxic protein accumulation, cell death, and failed recovery of transformants.

Purpose of the Study:

• To engineer a modified shuttle vector that mitigates toxicity issues in E. coli.
• To enable efficient recombinant protein expression in K. lactis while preventing uncontrolled expression in E. coli.

Main Methods:

• Construction of a modified shuttle vector incorporating a K. lactis ribosomal intron.
• Testing the vector's functionality in both E. coli and K. lactis.
• Evaluating the intron's role as a translational terminator in E. coli and its splicing in K. lactis.

Main Results:

• The modified shuttle vector effectively functions as a translational terminator in E. coli due to the presence of the K. lactis ribosomal intron.
• This prevents or significantly reduces the expression of potentially toxic recombinant proteins in E. coli transformants.
• In K. lactis, the intron is spliced from mRNA, allowing for the production of full-length, active recombinant proteins.

Conclusions:

• The engineered ribosomal intron serves as a crucial safety mechanism in shuttle vectors, preventing E. coli toxicity.
• This improved vector design facilitates the reliable manipulation and expression of recombinant DNA across prokaryotic and eukaryotic systems.
• The study enhances the utility of shuttle vectors for molecular biology and biotechnology applications involving yeast expression systems.