Doxycycline-induced bioluminescence in the mammary gland of the MTB/Cat^TMILA bigenic.

(A) Overlay of full-body bioluminescence and x-ray images of monogenic control (G6719 (ear tag#)) and MTB/Cat^TMILA bigenic (G6718 (ear tag#)) mice following 0, 24, and 48 hours of doxycycline intake. By 24 hours of doxycycline administration, bioluminescence activity is detected in the #2, #3 (thoracic), and #4 (inguinal) mammary glands of the MTB/Cat^TMILA bigenic (G6718) but not in the monogenic control mouse (G6719). (B) Whole mount of mammary gland from monogenic control mouse (G6719) shows normal ductal morphogenesis (black arrowhead) following 1-week of doxycycline administration. (C) Mammary gland whole mount analysis shows precocious lobuloalveologenesis (white arrowhead) in the similarly treated MTB/Cat^TMILA bigenic (G6718). Scale bar in (B) applies to (C); see S1 Fig for corresponding low magnification images. (D) Myc-epitope tag immunohistochemistry does not detect myc-epitope tagged ΔN89β-catenin expression in the mammary epithelium of the doxycycline treated monogenic (G6719) control (black arrowhead). (E) Myc-tagged ΔN89β-catenin expression is clearly detected in the mammary epithelium of the similarly treated MTB/Cat^TMILA bigenic (white arrowhead); (F) is a higher magnification of (E). (G) Image shows a representative transverse section of an epithelial duct in the mammary gland of the doxycycline-treated monogenic (G6719) control mouse, which scores negative for BrdU incorporation following BrdU immunohistochemistry (black arrowhead). (H) Numerous cells scoring positive for BrdU incorporation are detected in the mammary epithelium of the similarly treated MTB/Cat^TMILA bigenic (white arrowhead); (I) is a higher magnification. Scale bar in (D) and (F) apply to (E, G, and H) and (I) respectively. See S1 Fig for more details and quantitation of BrdU positive cells in the mammary epithelium of both genotypes following doxycycline administration.