Gene targeting in mouse embryos mediated by RecA and modified single-stranded oligonucleotides

Area of Science:

• Molecular Biology
• Genetics
• Biotechnology

Background:

• Gene targeting is crucial for understanding gene function but conventional methods using embryonic stem cells are complex and costly.
• Developing simpler, more efficient gene targeting techniques is essential for broader research applications.

Purpose of the Study:

• To develop a simplified gene targeting procedure utilizing E. coli recombinase A (RecA) and modified single-stranded oligonucleotides.
• To demonstrate the feasibility of this new method by targeting the HPRT gene in mouse embryos.

Main Methods:

• A 74-base single-stranded oligonucleotide with exonuclease-resistant linkages was designed to target exon 3 of the HPRT gene.
• The oligonucleotide was complexed with RecA to enhance homologous recombination before microinjection into mouse zygotes.
• Polymerase chain reaction (PCR) and sequencing were used to analyze nucleotide conversion in resulting blastocysts.

Main Results:

• The RecA-oligonucleotide complex was successfully microinjected into mouse zygotes.
• Analysis of blastocysts revealed a TAT to TAG stop codon conversion in the HPRT gene in 6.25% of cases (3 out of 48).
• This nucleotide conversion resulted in the loss of HPRT gene function.

Conclusions:

• The study demonstrates a feasible, simpler, and more direct method for gene targeting in mouse embryos.
• The use of RecA and single-stranded oligonucleotides offers a promising alternative to conventional gene targeting techniques.
• This approach has the potential to accelerate gene function studies and genetic engineering applications.