Inducible targeting of CNS astrocytes in Aldh1l1-CreERT2 BAC transgenic mice.

Jan Winchenbach,Klaus-Armin Nave,Gesine Saher,Tim Düking,Swen Hülsmann,Stefan A Berghoff,Sina K Stumpf

doi:10.12688/f1000research.10509.1

Abstract

Background: Studying astrocytes in higher brain functions has been hampered by the lack of genetic tools for the efficient expression of inducible Cre recombinase throughout the CNS, including the neocortex. Methods: Therefore, we generated BAC transgenic mice, in which CreERT2 is expressed under control of the Aldh1l1 regulatory region. Results: When crossbred to Cre reporter mice, adult Aldh1l1-CreERT2 mice show efficient gene targeting in astrocytes. No such Cre-mediated recombination was detectable in CNS neurons, oligodendrocytes, and microglia. As expected, Aldh1l1-CreERT2 expression was evident in several peripheral organs, including liver and kidney. Conclusions: Taken together, Aldh1l1-CreERT2 mice are a useful tool for studying astrocytes in neurovascular coupling, brain metabolism, synaptic plasticity and other aspects of neuron-glia interactions.

Highlights

Cre-mediated recombination of target genes in adult astrocytes requires the use of an inducible expression system, because many promoters of the astrocyte lineage are active in multipotential neural stem cells in the subventricular and subgranular zones (Christie et al, 2013)
Three lines of BAC transgenic mice were obtained by pronuclear injection, and crossbred with the Cre reporter mice ROSA26-Tdto or ROSA26-Eyfp (Madisen et al, 2010; Srinivas et al, 2001)
Based on the degree of expression, one of the three lines of aldehyde dehydrogenase 1 family member L1 (Aldh1l1)-CreERT2 mice was selected for detailed characterization of double-transgenic offspring

Summary

Introduction

Cre-mediated recombination of target genes in adult astrocytes requires the use of an inducible expression system, because many promoters of the astrocyte lineage are active in multipotential neural stem cells in the subventricular and subgranular zones (Christie et al, 2013). Transgenic mouse lines have been generated for tamoxifen-inducible Cre recombination of target genes in mature astrocytes (Chow et al, 2008; Ganat et al, 2006; Hirrlinger et al, 2006; Mori et al, 2006; Slezak et al, 2007). Aldh1l1 is regarded a pan-astrocyte marker, as determined in BAC transgenic mice with a fluorescent reporter protein or constitutive Cre expression under control of the Aldh1l1 promoter (Heintz, 2004; Yang et al, 2011). We selected the Aldh1l1 regulatory region and a similar BAC transgenic strategy to target transgenic expression of CreERT2 to mature astrocytes

Results and discussion

Conclusion

Methods