Integrins have been shown to play important roles in embryonic development, wound healing, metastasis, and other biological processes. alpha v beta 5 is a receptor for RGD-containing extracellular matrix proteins that has been suggested to be important in cutaneous wound healing and adenovirus infection. To examine the in vivo function of this receptor, we have generated mice lacking beta 5 expression, using homologous recombination in embryonic stem cells. Mice homozygous for a null mutation of the beta 5 subunit gene develop, grow, and reproduce normally. Keratinocytes harvested from beta 5(-/-) mice demonstrate impaired migration on and adhesion to the alpha v beta 5 ligand, vitronectin. However, the rate of healing of cutaneous wounds is not different in beta 5(-/-) and beta 5(+/+) mice. Furthermore, keratinocytes and airway epithelial cells obtained from null mice show adenovirus infection efficiency equal to that from wild-type mice. These data suggest that alpha v beta 5 is not essential for normal development, reproduction, adenovirus infection, or the healing of cutaneous wounds.