Generation of Car4 ^CreER mice and high-magnification views of microtubules in lung cells. (A) CRISPR targeting of the Car4 locus. The gRNA sequence is shown with the protospacer adjacent motif (PAM; not included in gRNA) underlined; a cryptic translation start codon of Car4 (ATG in red) is replaced by that of CreER. Locus-specific PCR genotyping identifies two positive mice. The primer sequences are: #1, 5′-TGT​ACT​GCT​ATT​CCT​TGT​TCA​TCT-3′; #2, 5′-AGA​AGC​ATT​TTC​CAG​GTA​TG-3′; #3, 5′-GTT​CGC​AAG​AAC​CTG​ATG​GAC​A-3′; #4, 5′-CTA​GAG​CCT​GTT​TTG​CAC​GTT​C-3′; #5, 5′-TTC​TAG​TTG​TGG​TTT​GTC​CAA​ACT-3′; #6, 5′-AAC​GTG​AAC​AGC​TAC​AAG​GCA​CTG-3′. (B)Car4^CreER targets Cap2 endothelial cells expressing ERG and CAR4 with characteristic large net-like morphology. Tam, 1 mg tamoxifen. Further characterization will be described in another study. Scale: 10 μm. (C) Filamentous microtubules are apparent in thin z stacks (<5 μm) of labeled AT2, AT1, and Cap2 cells (arrowhead and bracket). n, nucleus. See Fig. 4 for experimental conditions. Scale: 10 μm. Source data are available for this figure: SourceData FS3.