These MEFs possess loxP sites on either side of the first coding exon of mouse TRF1 (Terf1) gene. TRF1 knockout can be done by transduction of Cre recombinase to the MEFs. This inducible TRF1 knockout MEF line is useful in studies of telomere biology.
Development of the cells:
A targeting vector was designed to place a loxP site just upstream of exon 1, and a loxP-flanked TK-neomycin cassette just downstream of exon 1 of the targeted gene. This construct was electroporated into 129P2/OlaHsd-derived E14 embryonic stem (ES) cells. Correctly targeted ES cells were then transiently transfected with a Cre recombinase-expressing plasmid. The resulting ES cells with the TRF1F genotype (neo selection cassette removed; leaving a single loxP site upstream of exon 1 and a single loxP site downstream of exon 1) were injected into recipient blastocysts. Chimeric mice were bred with C57BL/6J mice to generate the TRF1F colony.
Infection of pBabe neo SV40-LT