Figure 4.

Protein levels of the PGR are significantly reduced in the Spop^d/d uterus. (A) Western immunoblot analysis shows that the A and B isoforms of PGR are significantly reduced in the Spop^d/d uterus as compared to controls. Expression levels of ESR1 are moderately increased in the Spop^d/d uterus compared to controls. The expression levels for SRC-3 are not significantly changed between control and Spop^d/d uteri; β-actin serves as the loading control. Note: each lane on the gel represents pooled protein samples from three individual mice. (B) Real-time PCR analysis shows that Pgr transcript levels are also significantly reduced in the Spop^d/d uterus (n = 4) as compared to controls (n = 4). (C) Immunohistochemical detection of PGR expression in the uterus of an ovariectomized control mouse. Note strong immunoreactivity for PGR in the luminal epithelium (LE) and glandular epithelium (GE). (D) Immunohistochemical detection of PGR expression in the uterus of an ovariectomized Spop^d/d mouse; note the significantly low levels of PGR expression in the luminal and glandular epithelial compartments. (E) and (F) are higher magnification images of (C) and (D) respectively; scale bar in (C) and (E) applies to (B) and (F), respectively.