Figure 1.

cDNA constructs introducing various deletions and point mutations into the cytoplasmic domain of Drosophila neuroglian. Truncations at the amino- and carboxyl-terminal end of the neuroglian¹⁶⁷ cytoplasmic domain, an internal deletion, and tyrosine to phenylalanine point mutations were generated by PCR as described in the Materials and Methods section. Lines represent the wild-type or mutated neuroglian cytoplasmic domains, starting at the first basic amino acid residue after the membrane-spanning segment and ending at the carboxy-terminus of the protein. The results of the yeast two-hybrid interaction between Drosophila ankyrin and the neuroglian cytoplasmic deletion proteins, as well as the ability of these deleted neuroglian molecules to induce S2 cell aggregation and to recruit ankyrin to S2 cell contacts are summarized on the righ.Wild-type activity levels are indicated with ++. At the bottom of the figure, cytoplasmic amino acid residues which are conserved in more than 90% of all known L1 family members are shown.