Fig. 3. m and dy encode transmembrane proteins with a ZP domain. (A) Genomic organisation of the m/dy region. The position of exons is indicated by black boxes. The regions deleted in the different deficiencies are shown below. The position of the small rearrangement present in the m¹ mutant is indicated (arrow). (B) Similarity diagrams based on a ClustalW multiple sequence alignment of the ZP domains from the indicated Drosophila, nematode and mammal proteins. (C) Predicted modular structure of Min, Dy and Dyl proteins (protein accession numbers are AAF48088, AAF48089 and AAF47884, respectively). The position of the transmembrane domain is highlighted by a vertical box. Tetrabasic RRR/AR motifs are indicated by triangles. Signal peptides are indicated by black boxes (SP). (D) Alignment of Dy, Dyl, Min and Cut-1 ZP domains. Black and shaded boxes indicate identical and similar residues, respectively. The position of the ZP structural domain is shown between brackets, and the eight conserved cysteines characteristic of this domain are marked with asterisks (see text for details).