Cre-mediated β-galactosidase expression in tissue sections of transgenic embryos.

<p>E17.5 embryos obtained after crossing CtsKCreERT2 positive or wild-type females with ROSA26 males were processed and stained for β-galactosidase activity as described under <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037592#s3" target="_blank">materials and methods</a>. <b>A</b>: E17.5 C57BL/6 wild-type control embryos; <b>a.1</b>: overview of β-gal activity; <b>a.2</b>, <b>a.3</b> and <b>a.6</b>: arms; <b>a.4</b> and <b>a.5</b>: legs; <b>a.7</b>: spinal cord <b>B</b>: E17.5 CtsKCreERT2+/−LacZ+/+ embryos (strain #4); <b>b.1</b>: overview of β-gal activity. <b>b.2</b> and <b>b.3</b>: arms; <b>b.4</b> and <b>b.5</b> legs; <b>b.6</b>: spinal cord. Arrows show positive β-galactosidase activity in bones. <b>C</b>: E17.5 CtsKCreERT2−/−LacZ+/+ embryos (strain #4); <b>c.1</b>: overview of β-gal activity; <b>c.2</b> and <b>c.3</b>: arms; <b>c.4</b> and <b>c.5</b>: legs; <b>c.6</b>: spinal cord.