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 coded for domains III, I/II, and G of laminin alpha., Construct rec alpha S coded for only the COOH- most 12% of the I/II domain and the G domain, The corresponding polypeptides were isolated and characterized from the culture media. The rec alpha L chain partly formed disulfide-linked heterotrimers with the endogenously produced beta and gamma laminin chains. Like normal Drosophila laminin, a substrate coating of either rec alpha L or rec alpha S supported neuron differentiation and neurite extension of primary Drosophila embryo cell cultures. However, at the same low concentrations, only Drosophila laminin-1, but neither rec alpha L nor rec alpha S supported myogenesis in these cultures. Previously, an overlapping set of dodecapeptides that covered a region of the murine laminin alpha 1 chain similar to rec alpha S had been synthesized and tested for cell culture support properties (Nomizu, M., Rim, 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 Drosophila laminin cu homologues of the six most active vertebrate dodecapeptides were now synthesized and tested as substrates for differentiation of primary Drosophila embryo cells. Peptides that contained either the Drosophila sequence SIKVGV or the murine homologue, SIKVAV, provided support for neurite extension.