Tissue-specific expression of a BAC transgene targeted to the Hprt locus in mouse embryonic stem cells. Journal   Genomics. Citation   Genomics. 83(6):1072-82 Publication date   2004 Jun Authors   Heaney JD Rettew AN Bronson SK Investigators   Sarah K. Bronson Grant agencies   National Institute of General Medical Sciences Grants   NIGMS T32-GM08619 MeSH headings   Chromosomes, Artificial, Bacterial Embryo, Mammalian Gene Targeting Hypoxanthine Phosphoribosyltransferase Stem Cells MeSH qualifiers   genetics cytology methods metabolism Abstract   The hypoxanthine phosphoribosyltransferase (Hprt) locus has been shown to have minimal influence on transgene expression when used as a surrogate site in the mouse genome. We have developed a method to transfer bacterial artificial chromosomes (BACs) as a single copy into the partially deleted Hprt locus of embryonic stem cells. BACs were modified by Cre/loxP recombination to contain the sequences necessary for homologous recombination into and complementation of the partially deleted Hprt locus. Modified BACs were shown to undergo homologous recombination into the genome intact, to be stably transmitted through the germ line of transgenic mice, and to be expressed in the proper tissue-specific manner. This technology will facilitate many studies in which correct interpretation of data depends on developmentally appropriate transgene expression in the absence of rearrangements or deletions of endogenous DNA.