Isolating cells from adult murine brain for validation of cell-type specific cre-mediated deletion

TheCre/loxP system allows for the temporal and spatial investigation of the expression of a single gene in the nervous system. Current methods of validating conditional knock-out mouse models rely on heterogeneous brain tissue or primary culture. These methods may assess the extent of genetic knockdown in the brain but do not provide age-appropriate, cell-type specific information.

We isolated specific cell types from adult murine brain using FACS to assess cell type-specific gene expression in conditional mouse models.

We identified robust but incomplete genetic knockdown in microglia isolated from two separate microglia-specific knockout models.

Genetic knockdown in isolated adult microglia differed significantly from cultured primary microglia.

Differences observed in primary cultured microglia compared to isolated adult microglia suggest that current methods used to validate microglia-specific gene deletion over-estimate deletion efficiency. Assessment of gene expression in isolated adult microglia provides a more accurate assessment of Cre-mediated gene deletion.