AldoC BAC-GFP transgenic mice as a reliable model for astrocyte identification and functional studies in the brain

Astrocytes, the most abundant glial cell type in the central nervous system (CNS), are essential for maintaining neural homeostasis, forming gliovascular unit, and modulating synaptic function. However, commonly used astrocytic markers often display regional variability or lack strict specificity, limiting their reliability for consistently identifying astrocytes across brain regions. To address this limitation, we generated a novel transgenic mouse line (AldoC BAC-GFP) that expresses green fluorescent protein (GFP) under the control of the aldolase C (AldoC) promoter using modified bacterial artificial chromosome (BAC) technology. AldoC is an enzyme abundantly expressed in astrocytes. We confirmed that GFP-expressing cells in these mice co-express endogenous AldoC and are co-labeled with established astrocytic markers, thereby validating their astrocytic identity. Importantly, GFP expression was largely restricted to astrocytes throughout diverse brain regions. Moreover, GFP-positive astrocytes in brain slices exhibited the characteristic linear-shaped passive conductance of mature astrocytes. Collectively, these findings demonstrate that AldoC BAC-GFP transgenic mice represent a reliable and broadly applicable model for functional studies of astrocytes in the CNS.