We have a Thy-1 GFP mouse in our colony. We maintain the mouse as homozygous because the heterozygous animal did not show a strong enough signal. There doesn't appear to be any issues with the line being homozygous. The issues start when we try to cross the line to another transgenic line. We have tried 3 times to cross Thy-1GFP to another transgenic line (3 different lines) and each time the Thy-1 GFP "disappears". We use a standard PCR rxn (can be found on Jax's website) to genotype the mice. Once we cross the Thy-1 GFP mice with another transgenic line, the PCR results are only negative. We rarely get a positive Thy-1 mouse from the cross and we never get any homozygous Thyy-1 mice for the cross. Is there something in the breeding scheme I am missing? Is there a reason why we keep loosing the Thy-1 GFP insertion? Any thoughts would be greatly appreciated!
Liz
hy1-GFP-S mice show EGFP labeling in the superficial layers of the neocortex, including most/all interneuron subtypes, with pyramidal/interneuron ratios of approximately 4:1 that match the distribution in the non-labeled population. While this is similar to Thy1-GFPM mice , the labeling distribution for line S is different from line M. In addition, less than 10% of cerebellum mossy fibers show EGFP labeling and no EGFP expression is observed in dorsal root ganglion of thy1-GFP-S mice.
(This information is from the Jackson Laboratory mouse data sheet 011070 )
Jai Ghosh - Thanks for your reply. I don't understand what the distribution of labeling has to do with the loss of the gene once the Thy-1 animal is mated to another transgenic line. Could you explain more?
Jai Ghosh Thanks Jai for your explanation. When we genotype mice for the transgene expressing Thy-1 GFP, we get no PCR product. Even if the expression of the gene was silenced, wouldn't we still be able to see the PCR product?
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