(D, E) Representative images (D) and quantification (E) of in-situ gelatin zymography of the labyrinth zone of murine WT and Cdkn2a-/-;p53-/- placentas on day E14.5. Scale bar, 50 μm. Data information: Values are means + SEM of at least three experimental repeats. Statistical significance was determined by unpaired two-tailed Student's t-test (*) p < 0.05; (**) p < 0.01; (***) P<0.001. 