NF-κB is required for the formation of Eda induced supernumerary mammary placodes.

(A-C) Expression of Tbx3 (A), Wnt10b (B) and PTHrP (C) was detected in the mammary buds of the WT, K14-Eda, IκBαΔN and compound IκBαΔN; K14-Eda embryos at E13.5. Arrows highlight the supernumerary mammary placodes in K14-Eda embryos. Note that no localized expression was visible between the 3^rd and the 4^th mammary bud in the compound IκBαΔN; K14-Eda embryos. (D) Scanning electron microscopy images of the mammary forming region confirmed absence of accessory mammary primordia in compound mutants. (Scale bar: 500 μm.)