What is gene targeting in mice?
To target genes in mice, the DNA is inserted into mouse embryonic stem cells in culture. Cells with the insertion can contribute to a mouse’s tissue via embryo injection. After this step the entire body of the mouse is based on the selected embryonic stem cell.
Which gene products are involved in homologous recombination?
The RecA/Rad51/DMC1 gene family plays a central role in homologous recombination during bacterial transformation as it does during eukaryotic meiosis and mitosis.
What does a target gene do?
Gene targeting (also, replacement strategy based on homologous recombination) is a genetic technique that uses homologous recombination to change an endogenous gene. The method can be used to delete a gene, remove exons, add a gene, and introduce point mutations.
What happens homologous recombination?
When recombination occurs during meiosis, the cell’s homologous chromosomes line up extremely close to one another. Then, the DNA strand within each chromosome breaks in the exact same location, leaving two free ends. Each end then crosses over into the other chromosome and forms a connection called a chiasma.
Does homologous recombination use ligase?
Here we have determined the effect of DNA ligase I-deficiency on the frequency of homologous recombination initiated by a site-specific DNA double-strand break. We found that expression of wild-type DNA ligase I in a human DNA ligase I mutant cell line significantly increased the frequency of homologous recombination.
What is homologous recombination and what is its outcome?
Homologous recombination (HR) is the genetic consequence of physical exchange between two aligned identical DNA regions on two separate chromosomes or on the same chromosome. HR mostly occurs between homologous chromosomes bearing distinct markers surrounding the exchange region.
What is a gene rearrangement?
Gene rearrangement is a phenomenon in which a programmed DNA recombination event occurs during cellular differentiation to reconstitute a functional gene from gene segments separated in the genome.
How is gene targeting used in the mouse?
Gene targeting by homologous recombination in ES cells is widely used to mutate and modify the mouse genome. Thereby the mouse is established as the most commonly used animal model system ( 1 ). With the exception of mice, most other mammalian species lack tools for targeted gene manipulation because functional ES cell lines are not established.
How is gene targeting used in embryonic stem cells?
Gene targeting by homologous recombination in embryonic stem cells is extensively used to generate specific mouse mutants. However, most mammalian species lack tools for targeted gene manipulation.
Why are zygotes used as a substrate for gene targeting?
Zygotes provide a logical substrate for the single-step modification of the mammalian germ line. Whereas pronuclear DNA injection is routinely used to generate transgenic mice, rats, and other mammals by random genomic integration of transgenes ( 14 – 16 ), gene targeting in zygotes is not established due to the low rate of spontaneous HR.