Aldh1l1-Cre/ER T2 is expressed in unintended cell types of the salivary gland, pancreas, and spleen.

The mouse is a widely used transgenic mouse model to conditionally express Cre recombinase in astrocytes of the central nervous system. Currently, no reports show whether the Cre recombinase activity, driven by the promoter, acts in cells outside of its intended astrocyte population. We crossed the mouse with a TdTomato reporter mouse line, ROSA26:CAG-LSL-TdTomato, to generate a fluorescent reporter for promoter activity. Gross anatomical observations reveal strong TdTomato expression in the spleen and exocrine glands-the salivary gland and the pancreas. We find TdTomato expression, a reporter of Cre activity, specifically targets serous cells in the parotid, submandibular, sublingual glands, and pancreas along with fibroblast-like cells within the submandibular lymph nodes and spleen. Our data indicate that the mouse model has unintended Cre recombinase activity in exocrine glands, which may influence biological and behavioral data.