AUTHOR=Caubit Xavier , Arbeille Elise , Chabbert Dorian , Desprez Florence , Messak Imane , Fatmi Ahmed , Habermann Bianca , Gubellini Paolo , Fasano Laurent 

TITLE=Camk2a-Cre and Tshz3 Expression in Mouse Striatal Cholinergic Interneurons: Implications for Autism Spectrum Disorder

JOURNAL=Frontiers in Genetics

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2021.683959

DOI=10.3389/fgene.2021.683959

ISSN=1664-8021

ABSTRACT=<p><italic>Camk2a-Cre</italic> mice have been widely used to study the postnatal function of several genes in forebrain projection neurons, including cortical projection neurons (CPNs) and striatal medium-sized spiny neurons (MSNs). We linked heterozygous deletion of <italic>TSHZ3/Tshz3</italic> gene to autism spectrum disorder (ASD) and used <italic>Camk2a-Cre</italic> mice to investigate the postnatal function of <italic>Tshz3</italic>, which is expressed by CPNs but not MSNs. Recently, single-cell transcriptomics of the adult mouse striatum revealed the expression of <italic>Camk2a</italic> in interneurons and showed <italic>Tshz3</italic> expression in striatal cholinergic interneurons (SCINs), which are attracting increasing interest in the field of ASD. These data and the phenotypic similarity between the mice with <italic>Tshz3</italic> haploinsufficiency and <italic>Camk2a-Cre</italic>-dependent conditional deletion of <italic>Tshz3</italic> (<italic>Camk2a-cKO</italic>) prompted us to better characterize the expression of <italic>Tshz3</italic> and the activity of <italic>Camk2a-Cre</italic> transgene in the striatum. Here, we show that the great majority of <italic>Tshz3</italic>-expressing cells are SCINs and that all SCINs express <italic>Tshz3</italic>. Using lineage tracing, we demonstrate that the <italic>Camk2a-Cre</italic> transgene is expressed in the SCIN lineage where it can efficiently elicit the deletion of the <italic>Tshz3-</italic>floxed allele. Moreover, transcriptomic and bioinformatic analysis in <italic>Camk2a-cKO</italic> mice showed dysregulated striatal expression of a number of genes, including genes whose human orthologues are associated with ASD and synaptic signaling. These findings identifying the expression of the <italic>Camk2a-Cre</italic> transgene in SCINs lineage lead to a reappraisal of the interpretation of experiments using <italic>Camk2a-Cre</italic>-dependent gene manipulations. They are also useful to decipher the cellular and molecular substrates of the ASD-related behavioral abnormalities observed in <italic>Tshz3</italic> mouse models.</p>