PRB inhibits NFκB activity.

<p><b>A,</b> Myometrial cells were transiently co-transfected with a NFκB luciferase construct (NFκB-Luc) and p65, with or without PRB. SG5 was used as control. MPA was added 24 h after transfection and the cells were incubated for another 24 h before luciferase assay. Data are expressed as median, 25^th and 75^th percentiles and range, and were analysed using paired <i>t</i> test. *indicates a significant difference of <i>p</i><0.05 and **, of <i>P</i><0.01 (n = 6). <b>B,</b> Myometrial cells were exposed to different stimuli, IL-1β, MPA and progesterone, either alone or in combination. mRNA was then extracted, and the COX-2 mRNA levels were measured using qPCR. Data are expressed as median, 25^th and 75^th percentiles and range, and were analysed using paired <i>t</i> test. ***indicates a significant difference of <i>p</i><0.001 (n = 12). <b>C,</b> Strep-tagged p65 (Strep-p65) and Halo-tagged PRA (HcA) or PRB (HcB) were transfected into myometrial cells as indicated. Parental halo-tag construct (HT2) was used as control. Cell lysates were then immunoprecipitated using anti-Strep antibody. The immunoprecipitates were examined by Western blotting using anti-Halo antibody. Input represented 10% of cell lysates used in the co-IP experiment.