Comparative analysis of CreER transgenic mice for the study of brain macrophages – a case study

Conditional mutagenesis and fate mapping have contributed considerably to our understanding of physiology and pathology. Specifically, Cre recombinase-based approaches allow the definition of cell type-specific contributions to disease development and of inter-cellular communication circuits in respective animal models. Here we compared Cx3cr1CreER and Sall1CreER transgenic mice and their use to decipher the brain macrophage compartment as a showcase to discuss recent technological advances. Specifically, we highlight the need to define the accuracy of Cre recombinase expression, as well as strengths and pitfalls of these particular systems that should be taken into consideration when applying these models. Overall design: We examined 4 individual mice from 2 different genotypes, the whole brain from each mouse was further divided into 4 samples: Sort, Sort+anti-HA IP, direct anti-HA IP and direct IgG IP.