The TRACER (Transposase and Recombinase-Associated Chromosomal Engineering Resource) database is a central resource describing mice and embryos carrying a transgenic insertion generated by a Sleeping Beauty transposon-based system (Ruf et al., 2011).
The transgenes used comprise different features. The transposons currently used most frequently (SB9 and SB8) contain:
A “regulatory sensor”
A LacZ gene driven by a minimal promoter. This promoter has no activity by itself but responds to the activities of the surrounding transcriptional regulatory elements around (warning: these elements can be quite far from the insertion site). For many insertions, the associated LacZ expression is described, in mid-gestation (E11-12) mouse embryos is described and annotated.
A tool for ”recombineering”
A loxP site, which can be used to initiate in vivo chromosomal rearrangements such as deletions, duplications or inversions when combined with another loxP (Hérault et al., 1998; Spitz et al., 2005; Wu et al., 2007)
As such, the insertions provide information about the surrounding regulatory landscape(s) and, for the ones available, can be used for in vivo CRE-mediated chromosomal re-engineering.
Importantly, the transgenes are flanked by the inverted repeats of a Sleeping Beauty transposon. Accordingly, each one can be “remobilized”, by breeding to a transgenic line expressing SB-transposase expressing transgenic line (Ruf et al., 2011). The remobilisation rate varies depending on the insertion site, but is usually very high (10-50%). In addition, since Sleeping Beauty is biased for “local hopping”, the new insertions are frequently observed (~ 15-30%) within 1 to 2 Mb from their starting site.
Hérault, Y., Rassoulzadegan, M., Cuzin, F., and Duboule, D. (1998). Engineering chromosomes in mice through targeted meiotic recombination (TAMERE). Nat Genet 20, 381–384.
Ruf, S., Symmons, O., Uslu, V.V., Dolle, D., Hot, C., Ettwiller, L., and Spitz, F. (2011). Large-scale analysis of the regulatory architecture of the mouse genome with a transposon-associated sensor. Nat Genet 43, 379–386.
Spitz, F., Herkenne, C., Morris, M.A., and Duboule, D. (2005). Inversion-induced disruption of the Hoxd cluster leads to the partition of regulatory landscapes. Nat Genet 37, 889–893.
Wu, Ying, Wu, and Capecchi (2007). Toward simpler and faster genome-wide mutagenesis in mice. Nat Genet.