Background on BACs and Recombineering
Bacterial Artificial Chromosomes (BACs) are ultra-low copy vectors that can hold up to 300 kb of foreign DNA and are stably propagated in E. coli. BACs can hold large genomic fragments from human, mouse or other species, making them ideal vectors for introduction of entire genes into the mouse or rat genome. BAC transgenes tend to faithfully recapitulate the expression pattern of endogenous genes due to their large size and inclusion of distant regulatory regions. BAC transgenic animals can be similar to knock-in models in the expression pattern of the gene of interest, with the advantage that the BAC is randomly integrated in the genome as a transgene rather than disrupting the endogenous gene. Several BAC libraries have been created and end-sequenced, making it easy to identify BAC clones harboring a gene of interest.
Because of their large size, BACs are difficult to modify by traditional restriction cloning methods. Recombineering is the modification of DNA using homologous recombination mechanisms in bacteria. Recombineering allows the precise modification of BACs to suit experimental purposes. Any desired modification can be introduced into a BAC, including insertion of reporter genes, point mutations, Lox-STOP-Lox conditional modifications, etc.
BAC Recombineering Services
The Animal Models Core has deep expertise in BAC recombineering and BAC transgenesis. We offer BAC recombineering services to assist clients in producing the BAC clones best suited for their transgenic experiments. BACs can be used to generate transgenic mice and rats for a variety of purposes. By inserting reporters such as GFP or lacZ into a BAC, the reporter can be expressed specifically in the tissues of interest. Insertion of Cre recombinase can produce a tissue-specific deleter strain. Point mutations can be introduced and the BAC used to express a mutant version of the protein. Human BACs can be introduced into mice or rats to produce humanized models. Recombineering allows the introduction of any desired modification into the BAC. Contact us for more information on options and pricing.