Cytosine deaminase gene as a positive selection marker

Area of Science:

• Biochemistry
• Molecular Biology
• Gene Therapy

Background:

• Cytosine deaminase (CD) is a non-mammalian enzyme catalyzing cytosine deamination.
• Genetically modified eukaryotic cells expressing bacterial CD enable negative selection systems with 5-fluorocytosine.
• Cancer gene therapy can benefit from precise cell selection strategies.

Purpose of the Study:

• To develop a novel positive selection method based on cytosine deaminase (CD) gene expression.
• To create a system where only cells expressing CD can survive under specific conditions.
• To offer an alternative to negative selection systems in genetic engineering and therapy.

Main Methods:

• Genetically modifying eukaryotic cells to express the bacterial cytosine deaminase gene.
• Utilizing inhibitors of the pyrimidine de novo synthesis pathway.
• Developing a positive selection medium requiring CD activity for cell survival.

Main Results:

• The developed method successfully selects for cells expressing the cytosine deaminase gene.
• Cells require the conversion of pyrimidine supplements to uracil by CD to survive.
• This establishes a functional positive selection system dependent on CD expression.

Conclusions:

• The novel positive selection method based on cytosine deaminase gene expression is effective.
• This system offers a valuable tool for applications requiring precise cell population selection.
• The method has potential implications for advancing cancer gene therapy and other genetic engineering fields.