Laminin-1 has previously been shown to be of major importance for the development of kidney tubules. Antibodies against fragments E8 and E3 of laminin-1 perturb kidney development in vitro. We here studied expression of integrins alpha 6 beta 1 and alpha 6 beta 4, two known laminin receptors, during kidney development. Integrin beta 1 subunit could be detected by immunofluorescence on all cell types of embryonic mouse kidney, but we could not detect integrin beta 4 subunit in embryonic kidney by immunofluorescence or by in situ hybridization. The presence of integrin alpha 6 subunit in all epithelia of embryonic kidney was demonstrated by immunofluorescence and by in situ hybridization. RT-PCR showed that alpha 6B is the major splice variant in embryonic kidney. During in vitro conversion of nephrogenic mesenchyme to epithelial tubules, a strong increase in the expression of the 6 kb mRNA for alpha 6 integrin subunit was seen by northern blotting at the onset of epithelial morphogenesis, on day two of culture. Immunoprecipitation of extracts from embryonic kidney with antibodies against alpha 6 subunit yielded bands corresponding to the expected size of beta 1 integrin subunit but not of beta 4 subunit. Monoclonal antibodies against either alpha 6 or beta 1 subunit but not against E-cadherin blocked kidney tubulogenesis in vitro. This suggests that integrin alpha 6B beta 1 is involved in kidney tubulogenesis in vitro. Another possibility is that the antibodies against integrin alpha 6 and beta 1 subunit cause abnormal signalling by the integrin.
Integrin alpha 6B beta 1 is involved in kidney tubulogenesis in vitro
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M. Falk, K. Salmivirta, M. Durbeej, E. Larsson, M. Ekblom, D. Vestweber, P. Ekblom; Integrin alpha 6B beta 1 is involved in kidney tubulogenesis in vitro. J Cell Sci 1 December 1996; 109 (12): 2801–2810. doi: https://doi.org/10.1242/jcs.109.12.2801
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