In vivo site-directed mutagenesis using oligonucleotides

Area of Science:

• Molecular Biology
• Genetics
• Yeast Genetics

Background:

• Functional gene characterization often relies on expression in model organisms like Saccharomyces cerevisiae.
• Existing methods for site-specific mutagenesis in yeast, such as in vitro mutagenesis or PCR-based approaches, can be inefficient, multistep, or limited by selectable phenotypes or restriction sites.

Purpose of the Study:

• To develop a rapid, cloning-free, in vivo method for site-specific DNA mutagenesis in yeast.
• To create a versatile system for generating various mutations, including base changes, insertions, and deletions, without retaining extraneous DNA.

Main Methods:

• The delitto perfetto system utilizes transformation with unpurified oligonucleotides in a two-step process.
• This method is dependent on the RAD52 gene and does not require subcloning or reliance on restriction sites.
• It allows for multiple rounds of mutation within a 200-base pair window.

Main Results:

• The delitto perfetto process efficiently generates site-specific mutations, including single/multiple base changes, insertions, and deletions.
• The system produces desired mutations without any heterologous DNA sequences.
• It is applicable to modifying DNA sequences from higher eukaryotes, such as mammalian DNA.

Conclusions:

• Delitto perfetto offers an efficient and rapid strategy for in vivo DNA mutagenesis in yeast.
• This cloning-free approach overcomes limitations of previous methods, enabling precise genetic modifications.
• The technique is valuable for functional genomics and for creating precise changes in DNA from various organisms, including mammals.