Mendelian transmission of Rosa26-targted CAGs-rtTA3 transgenes.

<p>*Numbers represent: observed (expected) from heterzygote x wild-type crosses.</p

GFP induction and mKate2 expression is uniform in most organs of <i>CAGs-rtTA3</i> and <i>CAGs-RIK</i> mice.

<p>Immunofluorescence stains for GFP and mKate2 in the small intestine and pancreas of ‘no rtTA’, <i>R26-rtTA</i>, <i>CAGs-rtTA3</i> and <i>CAGs-RIK</i> mice following 1 week of doxycycline treatment. All rtTA strains show strong GFP induction in small intestine (<b>A</b>), but only <i>CAGs-rtTA3</i> and <i>CAGs-RIK</i> show robust and uniform GFP expression (and mKate2 for <i>RIK</i>) in the pancreatic acinar tissue (<b>B</b>).</p

Adenoviral Cre induces mosaic activation of rtTA and GFP induction in <i>CAGs-LSL-rtTA3</i> and <i>CAGs-LSL-RIK</i> animals.

<p><b>A</b>. Immunofluorescent stains for GFP and mKate2 in liver sections of <i>TG-Ren.713;CAGs-LSL-rtTA3</i> and <i>TG-Ren.713;CAGs-LSL-RIK</i> mice 1 week following intravenous injection of Adenoviral Cre (5×10⁸ PFU) or PBS (<i>CAGs-LSL-RIK</i> only – left panel) and dox treatment. Double transgenic mice exposed to AdenoCre show mosaic expression of GFP (<i>CAGs-LSL-rtTA3</i>) or GFP and mKate2 (<i>CAGs-LSL-RIK</i>). No GFP of mKate2 expression was observed in animals not exposed to Cre. <b>B</b>. Immunofluorescent stains for GFP and mKate2 in lung sections of triple transgenic mice (<i>CAGs-LSL-rtTA3 or RIK;TG-Ren.713;LSL-Kras^G12D</i>). Kras^G12D-induced lung adenomas show strong expression of GFP and mKate2. Lowe panel: higher magnification of the lesion. White arrows indicate rare cells that show mKate2, but not GFP expression.</p

CAGs-rtTA3 and CAGs-RIK show strong expression in adult tissues.

<p>Whole mount epifluorescence images of small intestine, skin, pancreas kidney and liver from <i>R26-rtTA</i>, <i>CAGs-rtTA3</i> and <i>CAGs-RIK</i> transgenic animals (all containing <i>TG-Ren.713</i>). <i>R26-rtTA</i> shows strong expression in intestine and skin but weak or patchy expression in most other solid organs. <i>CAGs-rtTA3</i> and <i>CAGs-RIK</i> show almost identical expression patterns in adult mice. <i>CAGs-RIK</i> mice show strong and consistent expression of mKate2.</p

<i>CAGs-LSL-RIK</i> enables tissue-restricted expression of <i>TRE</i>-transgenes in transgenic models of disease.

<p><b>A</b>. Whole mount epifluorescence (top panel) and immunofluorescence images from a quadruple transgenic (<i>CAGs-LSL-RIK;TG-Ren.713;LSL-Kras^G12D;Pdx1-Cre</i>) animal, showing induction of GFP and mKate2 in both normal acinar tissue and pre-neoplastic, Kras^G12D-induced PanIN lesions (top arrow). As observed in AdenoCre treated lungs, some PanIN lesions did not show GFP or mKate2 staining suggesting incomplete LSL excision in a small proportion of cells. <b>B</b>. Immunofluorescent stains for GFP and mKate2 in mammary tissue of <i>CAGs-LSL-RIK;TG-Ren.713;MMTV-Neu;WAP-Cre</i> transgenic mice treated with dox.</p