Expression Patterns of Inducible Cre Recombinase Driven by Differential Astrocyte-Specific Promoters in Transgenic Mouse Lines
Neng-Yuan Hu1 • Ya-Ting Chen1 • Qian Wang1 • Wei Jie1 • Yi-Si Liu1 • Qiang-Long You1 • Ze-Lin Li1 • Xiao-Wen Li1 • Sophie Reibel2 • Frank W. Pfrieger3 • Jian-Ming Yang1 • Tian-Ming Gao 1
1 State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong–Hong Kong–Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangdong Key Laboratory of Psychiatric Disorders, Collaborative Innovation Center for Brain Science, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
2 Chronobiotron – UMS 3415, University of Strasbourg, 67084 Strasbourg, France
3 Institute of Cellular and Integrative Neurosciences, CNRS UPR 3212, University of Strasbourg, 67084 Strasbourg, France
Astrocytes are the most abundant cell type in the central nervous system (CNS). They provide trophic support for neurons, modulate synaptic transmission and plasticity, and contribute to neuronal dysfunction. Many transgenic mouse lines have been generated to obtain astrocyte-specific expression of inducible Cre recombinase for functional studies; however, the expression patterns of inducible Cre recombinase in these lines have not been systematically characterized. We generated a new astrocyte-specific Aldh1l1-CreERT2 knock-in mouse line and compared the expression pattern of Cre recombinase between this and five widely-used transgenic lines (hGfap-CreERT2 from The Jackson Laboratory and The Mutant Mouse Resource and Research Center, Glast-CreERT2, Cx30-CreERT2, and Fgfr3-iCreERT2) by crossing with Ai14 mice, which express tdTomato fluorescence following Cre-mediated recombination. In adult Aldh1l1-CreERT2:Ai14 transgenic mice, tdTomato was detected throughout the CNS, and five novel morphologically-defined types of astrocyte were described. Among the six evaluated lines, the specificity of Cre-mediated recombination was highest when driven by Aldh1l1 and lowest when driven by hGfap; in the latter mice, co-staining between tdTomato and NeuN was observed in the hippocampus and cortex. Notably, evident leakage was noted in Fgfr3-iCreERT2 mice, and the expression level of tdTomato was low in the thalamus when Cre recombinase expression was driven by Glast and in the capsular part of the central amygdaloid nucleus when driven by Cx30. Furthermore, tdTomato was clearly expressed in peripheral organs in four of the lines. Our results emphasize that the astrocyte-specific CreERT2 transgenic lines used in functional studies should be carefully selected.
Astrocytes; Cre recombinase; Expression pattern; Aldh1l1; Morphology