Homozygous mice are viable with no histologically observable abnormalities. Homozygotes do not express the targeted gene in lung, kidney, heart, aorta, liver, skin, and eye. Homozygous mice have a 15% decrease in body weight compared to wild type. Endothelial cells derived from wild type mice form tube-shaped primitive blood vessels structures. Cultured aortic endothelial cells from homozygote mutants display an attenuated ability to form tubes, suggesting diminished angiogenic potential. Cultured cells from mutant mice also exhibit a decreased migratory response to basic fibroblast growth factor in vitro. Following injection with melanoma and Lewis lung carcinoma cells, homozygous mice show retarded tumor growth correlated with decreased angiogenesis. This mouse may be useful in studies of cellular adhesion, vascular integrity, and angiogenesis, as well as pathologic blood vessel assembly.
