Efficient FLP recombination in mouse ES cells and oocytes.

Area of Science:

• * Molecular Biology
• * Genetics
• * Developmental Biology

Background:

• * The FLP/FRT site-specific recombination system is widely used for genetic manipulation.
• * Efficient and reliable methods for transient expression of FLP recombinase are crucial for applications in mouse models.
• * Existing vectors may have limitations in efficiency or applicability.

Purpose of the Study:

• * To report an improved vector, pCAGGS-FLPe, for enhanced transient expression of FLP recombinase.
• * To evaluate the efficacy of pCAGGS-FLPe in mouse embryonic stem (ES) cells and oocytes.
• * To provide practical options for the removal of FRT (Flippase Recognition Target) cassettes in mice.

Main Methods:

• * Construction and validation of the pCAGGS-FLPe vector.
• * Transfection of mouse ES cells with pCAGGS-FLPe.
• * Microinjection of pCAGGS-FLPe into mouse oocytes.
• * Assessment of FLP recombination efficiency and patterns.

Main Results:

• * Standard transfection of ES cells resulted in FLP recombination in approximately 6% of colonies, with some mosaicism observed.
• * Microinjection into oocytes led to complete FLP recombination in about one-third of resulting heterozygotic mice.
• * The pCAGGS-FLPe vector demonstrated practical utility in both ES cells and oocytes.

Conclusions:

• * The pCAGGS-FLPe vector provides an effective means for transient FLP recombinase expression.
• * This vector offers two distinct and practical strategies for FRT cassette removal in mouse genetic engineering.
• * pCAGGS-FLPe enhances the toolkit for precise genetic modifications in mouse models.