The ability to introduce exogenous DNA into animal models has provided insights into developmental biology, gene regulation, and the genetic basis of human disease. However, the capacity of traditional small plasmid and transposon vectors is limited to a few thousand base pairs, leading to the loss of certain regulatory elements necessary to confer accurate transgene expression in vivo. As a result, relatively low expression levels and positional effects can be produced. In order to circumvent these drawbacks, Creative Biolabs uses microinjection of bacterial artificial chromosomes (BACs) vectors, which is developed to enable insertion of large DNA clones.
Introduction of Bacterial Artificial Chromosomes (BACs)
Bacterial artificial chromosomes (BACs) are large-insert DNA clones based on the E. coli fertility factor. Besides the ability to contain transgenes as large as 500 kb, BACs have many other advantages, making them a preferred and primary choice for transgenic model creation.
First, the large DNA fragment contained in the BAC (100-300 kb) is more resistant to chromosomal position effects and is more likely to contain all the cis genomic elements required for conferring authentic gene expression patterns. Moreover, they are quite easy to work with, one can easily isolate a large quantity of high quality, relatively intact BAC DNA. Third, the recently developed recombineering method has enabled precise modification of BAC DNA molecules. BACs, therefore, have gained in popularity in generating transgenic mouse lines.
How to Generate BAC Transgenic Mice?
The most rapid and effective method to generate BAC transgenic mice is the direct microinjection of BAC DNA into the pronucleus of fertilized mouse eggs. In addition, BACs can be injected into mouse embryonic stem (ES) cells to obtain transgenic mice from germline ES cell-mouse chimeras. Because BAC transgenes usually include enough genomic DNA to confer endogenous gene expression patterns, ES cell clones can be prescreened for its expression to omit the additional time and technical manipulations required for processes like recombineering of drug selection cassettes. In summary, BAC transgenesis by microinjection is an effective and efficient method to produce genetically engineered mouse models.
At Creative Biolabs, both injections of BACs with large insertions and plasmid vectors are practically available. Once your model is generated, Creative Biolabs can breed, test, characterize and/or distribute it on your behalf, drawing on six decades of breeding and worldwide distribution experience for an efficient, single-source solution.
Meanwhile, Creative Biolabs offers the most up to date and comprehensive model creation services besides microinjection methods, please see below for more information:
Contact us or directly send us an inquiry to create the most optimal customized mouse model for your next project and beyond.
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