CONSERVED NEURON PROMOTING ACTIVITY IN DROSOPHILA AND VERTEBRATE LAMININ ALPHA-1

Drosophila S2 cells were transfected with constructs that code for two portions of the Drosophila laminin cu chain. Construct rec alpha L co ded for domains III, I/II, and G of laminin alpha., Construct rec alph a S coded for only the COOH- most 12% of the I/II domain and the G dom ain, The corresponding polypeptides were isolated and characterized fr om the culture media. The rec alpha L chain partly formed disulfide-li nked heterotrimers with the endogenously produced beta and gamma lamin in chains. Like normal Drosophila laminin, a substrate coating of eith er rec alpha L or rec alpha S supported neuron differentiation and neu rite extension of primary Drosophila embryo cell cultures. However, at the same low concentrations, only Drosophila laminin-1, but neither r ec alpha L nor rec alpha S supported myogenesis in these cultures. Pre viously, an overlapping set of dodecapeptides that covered a region of the murine laminin alpha 1 chain similar to rec alpha S had been synt hesized and tested for cell culture support properties (Nomizu, M., Ri m, W. H., Yamamura, K., Utani, A., Otaka, A., Roller, P. P., Kleinman, H. K., and Yamada, Y. (1995) J. Biol. Chem. 270, 20583-20590). The Dr osophila laminin cu homologues of the six most active vertebrate dodec apeptides were now synthesized and tested as substrates for differenti ation of primary Drosophila embryo cells. Peptides that contained eith er the Drosophila sequence SIKVGV or the murine homologue, SIKVAV, pro vided support for neurite extension.