Targeted integration of the Ren-1D locus in mouse embryonic stem cells

Area of Science:

• Genetics
• Molecular Biology
• Cardiovascular Physiology

Background:

• Mammalian cells possess highly homologous gene pairs, such as the mouse renin genes Ren-1D and Ren-2, presenting challenges for targeted genetic manipulation.
• Understanding the specificity of homologous recombination is crucial for gene editing technologies and studying gene function.

Purpose of the Study:

• To investigate the specificity of gene targeting via homologous recombination between the highly homologous mouse renin genes Ren-1D and Ren-2.
• To develop a method for creating targeted mutations in renin genes for functional studies.

Main Methods:

• Introduction of a Ren-1D targeting vector into embryonic stem cells containing both Ren-1D and Ren-2 genes.
• Utilizing a polymerase chain reaction (PCR) screen to detect targeted integration events at both the Ren-1D and Ren-2 loci.
• Analysis of gene conversion events in isolated embryonic stem cell clones.

Main Results:

• Fifteen targeted embryonic stem cell clones were isolated, all exhibiting a gene conversion event specifically at the Ren-1D locus.
• No clones were identified where the targeting vector recombined with the Ren-2 gene, despite >95% homology in the targeted region.
• These findings indicate that the homologous recombination machinery can differentiate between the Ren-1D and Ren-2 sequences.

Conclusions:

• The homologous recombination machinery in mammalian cells demonstrates specificity, capable of distinguishing between highly similar sequences like Ren-1D and Ren-2.
• The successful targeting of Ren-1D provides a foundation for generating transgenic mice with mutated renin genes.
• These genetically modified mice will enhance the understanding of Ren-1D and Ren-2 gene functions and their roles in cardiovascular homeostasis.