The 2-micron plasmid as a nonselectable, stable, high copy number yeast vector

Area of Science:

• Molecular and Cellular Biology
• Yeast Genetics
• Biotechnology

Background:

• The 2-microns plasmid is a native yeast episome crucial for cloning and expression vectors.
• Standard 2-microns-based vectors often suffer from reduced copy number and instability under non-selective conditions.
• There is a need for yeast vectors that retain high copy number and stability without continuous selection.

Purpose of the Study:

• To develop a method for constructing yeast vectors using the 2-microns plasmid without compromising copy number or stability.
• To identify suitable sites for genetic insertion within the 2-microns plasmid that preserve its native functions.
• To demonstrate the utility of a recombination chimera for creating stable, high-copy yeast vectors.

Main Methods:

• Identification of functional sites within the 2-microns plasmid for genetic manipulation.
• Construction and in vivo assessment of modified 2-microns plasmid vectors.
• Utilizing the pBH-2L recombination chimera for vector construction.
• Cloning yeast DNA fragments into the HpaI site near the STB element.

Main Results:

• Specific sites were identified for inserting genetic sequences without disrupting essential 2-microns coding elements.
• The HpaI site near the STB element allows cloning of DNA inserts up to 3.9 kb.
• Constructed plasmids maintained high copy numbers, comparable to the endogenous 2-microns plasmid.
• Plasmid stability was not compromised by the insertion of large DNA fragments.

Conclusions:

• The 2-microns plasmid can be engineered into a stable, high-copy number yeast vector system.
• Utilizing specific sites like HpaI near STB enables robust vector construction.
• This approach overcomes limitations of current yeast vectors, facilitating advanced genetic engineering applications.