The 3.1 kb Stra8.iCre transgene was designed with the 1.4 kb mouse Stra8 (mouse stimulated by retinoic acid gene 8) genomic promoter
fragment (containing the entire promoter region from -1400 to +7), an SV40 splice donor/splice acceptor region, an optimized variant of Cre recombinase (iCre; improved with mammalian codon usage, removed putative cryptic splce sites, altered stop codon, and reduced CpG content to limit the chances of epigenetic silencing in mammals), and an SV40 polyA signal. The transgene was microinjected into the pronucleus of fertilized FVB eggs. The single founder male exhibiting germline expression of the transgene was generated. The donating investigator reports the resulting Stra8-cre mice were subsequently bred to wild-type FVB/NJ mice for many generations prior to arrival at The Jackson Laboratory Repository. Upon arrival, the Stra8-cre transgenic mice were bred to FVB/NJ inbred mice (Stock No. 001800) to establish the colony.
A 27 SNP (single nucleotide polymorphism) panel analysis performed by The Jackson Laboratory on the rederived mice revealed nine segregating markers (eight different chromosomes). Four of the loci indicate C57BL/6, while the other five loci may be C57BL/6 or other (July 2009).
