The transgene consists of a mouse insulin promoter, (MIP, Ins2) driving a trifusion imagining reporter consisting of a bioluminescent reporter from a modified firefly luciferase gene (luc) fused to a fluorescent reporter, enhanced green fluorescent protein (EGFP) derived from the jellyfish Aequorea Victoria, which is fused to a positron emission tomography reporter, herpes simplex virus 1 sr39 thymidine kinase (HSV-1 sr39-TK).
This Ins2-luc/EGFP/Tk transgene (commonly referred to as MIP-TF) was microinjected into C57BL/6 embryos. Several founders were identified and evaluated. The donating investigator reported that founder line 300 has been maintained on a C57BL/6 background (see SNP note below). In 2010, The T1DR received this transgenic strain and mated to C57BL/6J for 1 generation prior to sibling mating.
A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. While the 27 markers throughout the genome suggested a C57BL/6 genetic background, all 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a C57BL/6N genetic background.
