Visualization of lymphatic vessels through NF-kappaB activity.

The molecular biology of lymphatics is only rudimentary owing to the long-standing absence of specific markers, and scanty is the information regarding bladder lymphatic vessels. By using mice with a reporter gene for nuclear factor kappaB (NF-kappaB) activity (kappaB-lacZ) in combination with immunohistochemical staining with a specific lymphatic marker (LYVE-1), we show, for the first time, that NF-kappaB is constitutively active in lymphatic endothelium in the urinary bladder, uterus, intestine, heart, and airways. Tie2-lacZ mice confirmed that the structures observed in kappaB-lacZ mice were not blood vessels.