THE DROSOPHILA GENE ESCARGOT ENCODES A ZINC FINGER MOTIF FOUND IN SNAIL-RELATED GENES

Two independent P-element enhancer detection lines were obtained that express lacZ in a pattern of longitudinal stripes early in germband el ongation. In this paper, molecular and genetic characterization of a g ene located near these transposons is presented. Sequence analysis of a cDNA clone from the region reveals that this gene has a high degree of similarity with the Drosophila snail gene (Boulay et al., 1987). Th e sequence similarity extends over 400 nucleotides, and includes a reg ion encoding five tandem zinc finger motifs (72% nucleotide identity; 76% amino acid identity). This region is also conserved in the snail h omologue from Xenopus laevis (76% nucleotide identity; 83% amino acid identity) (Sargent and Bennett, 1990). We have named the Drosophila sn ail-related gene escargot (esg), and the region of sequence conservati on common to all three genes the 'snailbox'. A number of Drosophila ge nomic DNA fragments cross-hybridize to a probe from the snailbox regio n suggesting that snail and escargot are members of a multigene family . The expression pattern of escargot is dynamic and complex. Early in germband elongation, escargot RNA is expressed in a pattern of longitu dinal stripes identical to the one observed in the two enhancer detect ion lines. Later in development, escargot is expressed in cells that w ill form the larval imaginal tissues. escargot is allelic with l(2)35C e, an essential gene located near snail in the genome.