Cre recombinase affects calcium dynamics already in young mice

As early as 3 months of age, Cre expression in VCMs leads to changes in Ca²⁺ dynamics that do not yet affect sarcomere shortening and cannot be attributed to the regulation of key proteins involved in Ca²⁺ dynamics. Because changes in intracellular Ca²⁺ dynamics can affect gene expression through altered excitation-transcription coupling, researchers should be aware of these subtle changes that precede the prominent phenotype at 6 months of age. Therefore, it is essential to use Cre-positive mice as controls when analyzing knockout models generated by the Cre/LoxP system.